LIGHT-EMITTING DEVICE INCLUDING ORGANOMETALLIC COMPOUND, ELECTRONIC DEVICE INCLUDING LIGHT-EMITTING DEVICE, AND THE ORGANOMETALLIC COMPOUND

Abstract

Embodiments provide a light-emitting device that includes a first electrode, a second electrode facing the first electrode, an interlayer between the first electrode and the second electrode and including an emission layer, and an organometallic compound represented by Formula 1, which is explained in the specification:

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and benefits of Korean Patent Application No. 10-2023-0020810 under 35 U.S.C. § 119, filed on Feb. 16, 2023, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

Embodiments relate to a light-emitting device including an organometallic compound, an electronic device including the light-emitting device, and the organometallic compound.

2. Description of the Related Art

Light-emitting devices may include a first electrode, a hole transport region, an emission layer, an electron transport region, and a second electrode, arranged in that order. Holes injected from the first electrode can move toward the emission layer through a hole transport region. Electrons injected from the second electrode can move toward the emission layer through an electron injection layer in the electron transport region. Carriers such as the holes and the electrons may combine in the emission layer to produce excitons. As the excitons transition from an excited state to a ground state, light may be generated.

It is to be understood that this background of the technology section is, in part, intended to provide useful background for understanding the technology. However, this background of the technology section may also include ideas, concepts, or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to a corresponding effective filing date of the subject matter disclosed herein.

SUMMARY

Embodiments include an organometallic compound capable of exhibiting improved color purity, improved stability, improved luminescence efficiency, and improved lifespan, and a light-emitting device and an electronic device which employ the organometallic compound.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the embodiments of the disclosure.

According to embodiments, a light-emitting device may include a first electrode, a second electrode facing the first electrode, an interlayer between the first electrode and the second electrode and including an emission layer, and an organometallic compound represented by Formula 1:

In Formula 1

• • M may be platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), or osmium (Os),
  • X₁ to X₄ may each independently be a carbon atom (C) or a nitrogen atom (N), rings CY₁ to CY₄ may each independently be a C₅-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,
  • L₁ to L₃ may each independently be *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—C(R₅)═*′ *═C(R₅)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₅)—*′, *—N(R₅)—*′,*—P(R₅)—*′, *—Si(R₅)(R₆)—*′, *—P(R₅)(R₆)—*′, or *—Ge(R₅)(R₆)—*′,
  • L₄ may be a C₅-C₆₀ carbocyclic group unsubstituted or substituted with R_10b or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with R_10b,
  • a1 to a3 may each independently be an integer from 0 to 3,
  • when a1 is 0, rings CY₁ and CY₂ may not be linked to each other via (L₁)_a1, and when a1 is 2 or 3, two or three of L₁ may be identical to or different from each other,
  • when a2 is 0, rings CY₂ and CY₃ may not be linked to each other via (L₂)_a2, and when a2 is 2 or 3, two or three of L₂ may be identical to or different from each other,
  • when a3 is 0, rings CY₃ and CY₄ may not be linked to each other via (L₃)_a3, and when a3 is 2 or 3, two or three of L₃ may be identical to or different from each other,
  • a4 may be an integer from 1 to 3,
  • when a4 is 2 or 3, two or three of L₄ may be identical to or different from each other,
  • a ring formed by M, X₁-containing CY₁, (L₄)_a4, and X₄-containing CY₄ may be a 9-membered ring,
  • R₁ to R₆ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkenyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkynyl group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ alkoxy group unsubstituted or substituted with at least one R_10a, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, a C₆-C₆₀ aryloxy group unsubstituted or substituted with at least one R_10a, a C₆-C₆₀ arylthio group unsubstituted or substituted with at least one R_10a, a C₇-C₆₀ arylalkyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ heteroarylalkyl group unsubstituted or substituted with at least one R_10a, —C(Q₁)(Q₂)(Q₃), —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂),
  • b1 to b4 may each independently be an integer from 0 to 10,
  • R_10b and R₁ may optionally be linked to each other to form a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group,
  • R_10b and R₄ may optionally be linked to each other to form a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group,
  • R_10a and R_10b may each independently be:
  • deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;
  • a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₂-C₆₀ heteroarylalkyl group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or any combination thereof;
  • a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, or a C₂-C₆₀ heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₂-C₆₀ heteroarylalkyl group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof; or
  • —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂), and
  • Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently be:
  • hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group; or
  • a C₃-C₆₀carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₇-C₆₀ arylalkyl group, or a C₂-C₆₀ heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.

In an embodiment, the interlayer may include the organometallic compound.

In an embodiment, the light-emitting device may further include a second compound including at least one π electron-deficient nitrogen-containing C₁-C₆₀ heterocyclic group, a third compound including a group represented by Formula 3, a fourth compound that is a delayed fluorescence compound, or any combination thereof, wherein the organometallic compound, the second compound, the third compound, and the fourth compound may be different from each other, and wherein Formula 3 is explained below.

In an embodiment, the interlayer may further include a hole transport region between the first electrode and the emission layer, and an electron transport region between the emission layer and the second electrode; the hole transport region may include a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or any combination thereof; the electron transport region may include a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or any combination thereof;

• • the emission layer may include: the organometallic compound; and the second compound, the third compound, the fourth compound, or any combination thereof, and
  • the emission layer may emit blue light.

According to embodiments, an electronic device may include the light-emitting device.

In an embodiment, the electronic device may further include: a thin-film transistor electrically connected to the light-emitting device; and a color filter, a color conversion layer, a touch screen layer, a polarizing layer, or any combination thereof.

According to embodiments, an electronic apparatus may include the light-emitting device, wherein the electronic apparatus may be a flat panel display, a curved display, a computer monitor, a medical monitor, a television, an advertisement board, an indoor light, an outdoor light, a signal light, a head-up display, a fully transparent display, a partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a mobile phone, a tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay, a three-dimensional (3D) display, a virtual reality display, an augmented reality display, a vehicle, a video wall including multiple displays tiled together, a theater screen, a stadium screen, a phototherapy device, or a signboard.

According to embodiments, an organometallic compound may be represented by Formula 1, which is explained herein.

In an embodiment, the organometallic compound may be represented by Formula 1-1 or Formula 1-2, which are explained below.

In an embodiment, at least one of rings CY₁ to CY₄ may each include a carbene moiety.

In an embodiment, rings CY₁ to CY₄ may each independently be a benzene group, a naphthalene group, a pyridine group, a pyridazine group, a pyrimidine group, a pyrazine group, a triazine group, a cyclopentadiene group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, a benzoimidazole group, an imidazopyridine group, an imidazopyrimidine group, imidazotriazine group, an imidazopyrazine group, or an imidazopyridazine group.

In an embodiment, rings CY₁ and CY₃ may each independently be a C₄-C₂₀ polycyclic group in which 2 to 4 C₃-C₈ monocyclic groups are condensed with each other; and rings CY₂ and CY₄ may each independently be a C₃-C₈ monocyclic group.

In an embodiment, in Formula 1, a moiety represented by

may be a moiety represented by Formula A1 or Formula A2, which are explained below.

In an embodiment, in Formula 1, a moiety represented by

may be a moiety represented by Formula A3, which is explained below.

In an embodiment, the organometallic compound may include at least four deuterium atoms.

In an embodiment, at least one L₄ may each independently be a group represented by one of Formulae 2-1 to 2-3, which are explained below.

In an embodiment, the organometallic compound may be represented by Formula 3-1 or Formula 3-2, which are explained below.

In an embodiment, when R_10c and R₁ are linked to each other, R_10c and R₁ may be linked to each other to form a 9-membered ring.

In an embodiment, in Formula 1, a moiety represented by

may be a moiety represented by one of Formulae 4-1 to 4-3, which are explained below.

In an embodiment, the organometallic compound may be one of Compounds BD1 to BD33, which are explained below.

It is to be understood that the embodiments above are described in a generic and explanatory sense only and not for the purposes of limitation, and the disclosure is not limited to the embodiments described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the disclosure will be more apparent by describing in detail embodiments thereof with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a light-emitting device according to an embodiment;

FIG. 2 is a schematic cross-sectional view of an electronic device according to an embodiment;

FIG. 3 is a schematic cross-sectional view of an electronic device according to another embodiment;

FIG. 4 is a schematic perspective view of an electronic apparatus including a light-emitting device according to an embodiment;

FIG. 5 is a schematic perspective view of an exterior of a vehicle as an electronic apparatus including a light-emitting device according to an embodiment; and

FIGS. 6A to 6C are each a schematic diagram of an interior of the vehicle of FIG. 5, according to embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In the drawings, the sizes, thicknesses, ratios, and dimensions of the elements may be exaggerated for ease of description and for clarity. Like numbers refer to like elements throughout.

In the specification, it will be understood that when an element (or region, layer, part, etc.) is referred to as being “on”, “connected to”, or “coupled to” another element, it can be directly on, connected to, or coupled to the other element, or one or more intervening elements may be present therebetween. In a similar sense, when an element (or region, layer, part, etc.) is described as “covering” another element, it can directly cover the other element, or one or more intervening elements may be present therebetween.

In the specification, when an element is “directly on,” “directly connected to,” or “directly coupled to” another element, there are no intervening elements present. For example, “directly on” may mean that two layers or two elements are disposed without an additional element such as an adhesion element therebetween.

In the specification, the expressions used in the singular such as “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In the specification, the term “and/or” includes any and all combinations of one or more of the associated listed items. For example, “A and/or B” may be understood to mean “A, B, or A and B.” The terms “and” and “or” may be used in the conjunctive or disjunctive sense and may be understood to be equivalent to “and/or”.

In the specification and the claims, the term “at least one of” is intended to include the meaning of “at least one selected from the group consisting of” for the purpose of its meaning and interpretation. For example, “at least one of A, B, and C” may be understood to mean A only, B only, C only, or any combination of two or more of A, B, and C, such as ABC, ACC, BC, or CC. When preceding a list of elements, the term, “at least one of,” modifies the entire list of elements and does not modify the individual elements of the list.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, a first element could be termed a second element without departing from the teachings of the disclosure. Similarly, a second element could be termed a first element, without departing from the scope of the disclosure.

The spatially relative terms “below”, “beneath”, “lower”, “above”, “upper”, or the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device illustrated in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in other directions and thus the spatially relative terms may be interpreted differently depending on the orientations.

The terms “about” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the recited value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the recited quantity (i.e., the limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±20%, ±10%, or ±5% of the stated value.

It should be understood that the terms “comprises,” “comprising,” “includes,” “including,” “have,” “having,” “contains,” “containing,” and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof in the disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless otherwise defined or implied herein, all terms (including technical and scientific terms) used have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an ideal or excessively formal sense unless clearly defined in the specification.

According to embodiments, a light-emitting device may include:

• • a first electrode;
  • a second electrode facing the first electrode;
  • an interlayer between the first electrode and the second electrode and including an emission layer; and
  • an organometallic compound represented by Formula 1:

Formula 1 will be explained below.

In embodiments, the light-emitting device may further include a capping layer outside the first electrode and/or outside the second electrode.

For example, the light-emitting device may further include at least one of a first capping layer disposed outside the first electrode and a second capping layer disposed outside the second electrode, and the organometallic compound represented by Formula 1 may be included in at least one of the first capping layer and the second capping layer.

In an embodiment, the light-emitting device may further include:

• • a first capping layer disposed outside the first electrode and including the organometallic compound represented by Formula 1;
  • a second capping layer disposed outside the second electrode and including the organometallic compound represented by Formula 1; or
  • the first capping layer and the second capping layer.

The wording “interlayer and/or capping layer includes an organometallic compound” as used herein may be understood as “interlayer and/or capping layer may include one type of organometallic compound represented by Formula 1 or two or more different types of organometallic compounds independently represented by Formula 1.”

For example, the interlayer and/or the capping layer may include Compound BD1 alone as the organometallic compound. In this regard, Compound BD1 may be present in the emission layer of the light-emitting device. In embodiments, the emission layer may include Compound BD1 and Compound BD2 as the organometallic compounds. In this regard, Compound BD1 and Compound BD2 may be present in a same layer (for example, both Compound BD1 and Compound BD2 may be present in the emission layer), or may be present in different layers (for example, Compound BD1 may be present in the emission layer and Compound BD2 may be present in the electron transport region).

The term “interlayer” as used herein refers to a single layer and/or all layers between the first electrode and the second electrode of a light-emitting device.

In an embodiment, the light-emitting device may further include:

• • a second compound including at least one π electron-deficient nitrogen-containing C₁-C₆₀ heterocyclic group, a third compound including a group represented by Formula 3, a fourth compound capable of emitting delayed fluorescence (for example, a delayed fluorescence compound), or any combination thereof,
  • wherein the organometallic compound, the second compound, the third compound, and the fourth compound may be different from each other:

In Formula 3

• • rings CY₇₁ and CY₇₂ may each independently be a π electron-rich C₃-C₆₀ cyclic group or a pyridine group,
  • X₇₁ may be: a single bond; or a linking group including O, S, N, B, C, Si, or any combination thereof, and
  • * indicates a binding site to any atom included in the remaining portion other than the group represented by Formula 3 in the third compound.

In an embodiment, the interlayer may include:

• • the organometallic compound; and
  • the second compound, the third compound, the fourth compound, or any combination thereof.

For example, the emission layer may include a composition including:

• • the organometallic compound; and
  • the second compound, the third compound, the fourth compound, or any combination thereof.

In an embodiment, an amount of the organometallic compound may be in a range of about 1 part by weight to about 20 parts by weight, with respect to 100 parts by weight of the emission layer. For example, an amount of the organometallic compound may be in a range of about 10 parts by weight to about 15 parts by weight, with respect to 100 parts by weight of the emission layer.

A layer including the composition may include a mixture including:

• • the organometallic compound; and
  • the second compound, the third compound, the fourth compound, or any combination thereof.

For example, “the layer including the composition” may include:

• • the organometallic compound and the second compound;
  • the organometallic compound and the third compound;
  • the organometallic compound and the fourth compound;
  • the organometallic compound, the second compound, and the third compound;
  • the organometallic compound, the second compound, and the fourth compound;
  • the organometallic compound, the third compound, and the fourth compound; or
  • the organometallic compound, the second compound, the third compound, and the fourth compound.

Therefore, “the layer including the composition” is clearly differentiated from, for example, a double layer consisting of: a first layer including the organometallic compound; and a second layer including the second compound, the third compound, the fourth compound, or any combination thereof.

In an embodiment, the composition may be a composition prepared to form a layer including: the organometallic compound; and the second compound, the third compound, the fourth compound, or any combination thereof, by using various methods such as a deposition method and a wet process. For example, the composition may be a pre-mixed mixture prepared for use in a deposition method (for example, a vacuum deposition method). The pre-mixed mixture may be charged, for example, into a deposition source inside a vacuum chamber, and two or more compounds included in the pre-mixed mixture may be co-deposited.

In an embodiment, the organometallic compound, the second compound, the third compound, and the fourth compound may each include at least one deuterium.

In an embodiment, the organometallic compound, the second compound, the third compound, and the fourth compound may each include at least one silicon.

In an embodiment, the composition and the light-emitting device may each further include the second compound other than the organometallic compound; and the second compound may include at least one deuterium, at least one silicon, or any combination thereof.

In an embodiment, the composition and the light-emitting device may each further include the third compound other than the organometallic compound; and the third compound may include at least one deuterium, at least one silicon, or any combination thereof.

In an embodiment, the composition and the light-emitting device may each further include the fourth compound other than the organometallic compound; and the fourth compound may include at least one deuterium, at least one silicon, or any combination thereof. For example, the fourth compound may serve to improve color purity, color conversion efficiency and lifespan of the light-emitting device.

In an embodiment, the composition and the light-emitting device may each further include the second compound and the third compound other than the organometallic compound; and at least one of the second compound and the third compound may each independently include at least one deuterium, at least one silicon, or any combination thereof. The second compound and the third compound may form an exciplex.

In an embodiment, the composition and the light-emitting device may each further include the second compound, the third compound, and the fourth compound other than the organometallic compound; and at least one of the second compound, the third compound, and the fourth compound may each independently include at least one deuterium, at least one silicon, or any combination thereof.

In an embodiment, a highest occupied molecular orbital (HOMO) energy level of the organometallic compound may be in a range of about −5.35 eV to about −4.55 eV. For example, a HOMO energy level of the organometallic compound may be in a range of about −5.30 eV to about −4.80 eV.

In an embodiment, a lowest unoccupied molecular orbital (LUMO) energy level of the organometallic compound may be in a range of about −2.20 eV to about −1.30 eV. For example, a LUMO energy level of the organometallic compound may be in a range of about −2.15 eV to about −1.45 eV.

The HOMO and LUMO energy levels may each be evaluated through cyclic voltammetry analysis of the organometallic compound.

In an embodiment, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 430 nm to about 475 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 440 nm to about 475 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 450 nm to about 475 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 430 nm to about 470 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 440 nm to about 470 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 450 nm to about 470 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 430 nm to about 465 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 440 nm to about 465 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 450 nm to about 465 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 430 nm to about 460 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 440 nm to about 460 nm. For example, a maximum emission wavelength (or an emission peak wavelength) of the organometallic compound may be in a range of about 450 nm to about 460 nm. For example, the emission layer including the organometallic compound may emit blue light. For example, the blue light may be deep blue light.

In an embodiment, a CIEx value (for example, bottom emission CIEx) of the blue light may be in a range of about 0.125 to about 0.140. For example, a CIEx value of the blue light may be in a range of about 0.130 to about 0.140.

In an embodiment, a CIEy value of the blue light (for example, bottom emission CIEy) may be in a range of about 0.110 to about 0.200. For example, a CIEy value of the blue light may be in a range of about 0.115 to about 0.160.

In an embodiment, the second compound may include a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or any combination thereof.

In an embodiment, the second compound may include a compound represented by Formula 2:

In Formula 2,

• • L₅₁ to L₅₃ may each independently be a single bond, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • b51 to b53 may each independently be an integer from 1 to 5,
  • X₅₄ may be N or C(R₅₄), X₅₅ may be N or C(R₅₅), X₅₆ may be N or C(R₅₆), and at least one of X₅₄ to X₅₆ may each be N,
  • R₅₁ to R₅₆ and R_10a are each the same as described herein.

In an embodiment, the second compound may include a carbazole group or a dibenzofuran group, and may be substituted with at least four deuterium atoms.

In an embodiment, the third compound may not be CBP or mCBP:

In an embodiment, the third compound may include a compound represented by Formula 3-11, a compound represented by Formula 3-12, a compound represented by Formula 3-13, a compound represented by Formula 3-14, a compound represented by Formula 3-15, or any combination thereof:

In Formulae 3-11 to 3-15,

• • rings CY₇₁ to CY₇₄ may each independently be a π electron-rich C₃-C₆₀ cyclic group or a pyridine group,
  • X₈₂ may be a single bond, O, S, N-[(L₈₂)_b82-R₈₂], C(R_82a)(R_82b), or Si(R_82a)(R_82b),
  • X₈₃ may be a single bond, O, S, N-[(L₈₃)_b83-R₈₃], C(R_83a)(R_83b), or Si(R_83a)(R_83b),
  • X₈₄ may be O, S, N-[(L₈₄)_b84-R₈₄], C(R_84a)(R_84b), or Si(R_84a)(R_84b),
  • X₈₅ may be C or Si,
  • L₈₁ to L₈₅ may each independently be a single bond, *—C(Q₄)(Q₅)—*′, *—Si(Q₄)(Q₅)—*′, a π electron-rich C₃-C₆₀ cyclic group unsubstituted or substituted with at least one R_10a, or a pyridine group unsubstituted or substituted with at least one R_10a, and Q₄ and Q₅ are each independently the same as described herein in connection with Q₁,
  • b81 to b85 may each independently be an integer from 1 to 5,
  • R₇₁ to R₇₄, R₈₁ to R₈₅, R_82a, R_82b, R_83a, R_83b, R_84a, and R_84b are each the same as described herein,
  • a71 to a74 may each independently be an integer from 0 to 20, and
  • R_10a may be the same as described herein.

In an embodiment, a difference between a triplet energy level (eV) of the fourth compound and a singlet energy level (eV) of the fourth compound may be in a range of about 0 eV to about 0.5 eV. For example, a difference between a triplet energy level (eV) of the fourth compound and a singlet energy level (eV) of the fourth compound may be in a range of about 0 eV to about 0.3 eV.

In an embodiment, the fourth compound may include at least one cyclic group including boron (B) and nitrogen (N) as a ring-forming atom. For example, the fourth compound may be a C₈-C₆₀ polycyclic group-containing compound including at least two condensed cyclic groups that share a boron (B) atom.

In an embodiment, the fourth compound may include a condensed ring in which at least one third ring may be condensed with at least one fourth ring,

• • the third ring may be a cyclopentane group, a cyclohexane group, a cycloheptane group, a cyclooctane group, a cyclopentene group, a cyclohexene group, a cycloheptene group, a cyclooctene group, an adamantane group, a norbornene group, a norbornane group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.2]octane group, a benzene group, a pyridine group, a pyrimidine group, a pyridazine group, a pyrazine group, or a triazine group, and
  • the fourth ring may be a 1,2-azaborinine group, a 1,3-azaborinine group, a 1,4-azaborinine group, a 1,2-dihydro-1,2-azaborinine group, a 1,4-oxaborinine group, a 1,4-thiaborinine group, or a 1,4-dihydroborinine group.

In an embodiment, the fourth compound may be a compound represented by Formula 502, a compound represented by Formula 503, or any combination thereof:

In Formulae 502 and 503,

• • rings A₅₀₁ to A₅₀₄ may each independently be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,
  • Y₅₀₅ may be O, S, N(R₅₀₅), B(R₅₀₅), C(R_505a)(R_505b), or Si(R_505a)(R_505b),
  • Y₅₀₆ may be O, S, N(R₅₀₆), B(R₅₀₆), C(R_506a)(R_506b), or Si(R_506a)(R_506b),
  • Y₅₀₇ may be O, S, N(R₅₀₇), B(R₅₀₇), C(R_507a)(R_507b), or Si(R_507a)(R_507b),
  • Y₅₀₈ may be O, S, N(R₅₀₈), B(R₅₀₈), C(R_508a)(R_508b), or Si(R_508a)(R_508b),
  • Y₅₁ and Y₅₂ may each independently be B, P(═O), or S(═O),
  • R_500a, R_500b, R₅₀₁ to R₅₀₈, R_505a, R_505b, R_506a, R_506b, R_507a, R_507b, R_508a, and R_508b are each the same as described herein, and
  • a501 to a504 may each independently be an integer from 0 to 20.

In the specification, R₅₁ to R₅₆, R₇₁ to R₇₄, R₈₁ to R₈₅, R_82a, R_82b, R_83a, R_83b, R_84a, R_84b, R_500a, R_500b, R₅₀₁ to R₅₀₈, R_505a, R_505b, R_506a, R_506b, R_507a, R_507b, R_508a and R_508b may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkenyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkynyl group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ alkoxy group unsubstituted or substituted with at least one R_10a, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, a C₆-C₆₀ aryloxy group unsubstituted or substituted with at least one R_10a, a C₆-C₆₀ arylthio group unsubstituted or substituted with at least one R_10a, —C(Q₁)(Q₂)(Q₃), —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂). Q₁ to Q₃ are each the same as described in the specification.

In an embodiment, the light-emitting device may satisfy at least one of Conditions 11 to 14:

[Condition 11]

LUMO energy level (eV) of the third compound >LUMO energy level (eV) of the organometallic compound;

[Condition 12]

LUMO energy level (eV) of the organometallic compound >LUMO energy level (eV) of the second compound;

[Condition 13]

HOMO energy level (eV) of the organometallic compound >HOMO energy level (eV) of the third compound;

[Condition 14]

HOMO energy level (eV) of the third compound >HOMO energy level (eV) of the second compound.

A highest occupied molecular orbital (HOMO) energy level and a lowest unoccupied molecular orbital (LUMO) energy level of the organometallic compound, the second compound, and the third compound may each be a negative value. The HOMO energy levels and the LUMO energy levels may each be measured according to a method of the related art, for example, a method described in Evaluation Example 1 in the specification.

In embodiments, an absolute value of a difference between the LUMO energy level of the organometallic compound and the LUMO energy level of the second compound may be in a range of about 0.1 eV to about 1.0 eV; an absolute value of a difference between the LUMO energy level of the organometallic compound and the LUMO energy level of the third compound may be in a range of about 0.1 eV to about 1.0 eV; an absolute value of a difference between the HOMO energy level of the organometallic compound and the HOMO energy level of the second compound may be less than or equal to about 1.25 eV (for example, in a range of about 0.2 eV to about 1.25 eV); or an absolute value of a difference between the HOMO energy level of the organometallic compound and the HOMO energy level of the third compound may be less than or equal to about 1.25 eV (for example, in a range of about 0.2 eV to about 1.25 eV).

When the relationships between the LUMO energy level and the HOMO energy level satisfy the conditions as described above, a balance between holes and electrons injected into the emission layer can be achieved.

According to embodiments, an electronic device may include the light-emitting device.

In an embodiment, the electronic device may further include: a thin-film transistor electrically connected to the light-emitting device; and a color filter, a color conversion layer, a touch screen layer, a polarizing layer, or any combination thereof.

According to embodiments, an electronic apparatus may include the light-emitting device, and the electronic apparatus may be a flat panel display, a curved display, a computer monitor, a medical monitor, a television, an advertisement board, an indoor light, an outdoor light, a signal light, a head-up display, a fully transparent display, a partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a mobile phone, a tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay, a three-dimensional (3D) display, a virtual reality display, an augmented reality display, a vehicle, a video wall with multiple displays tiled together, a theater screen, a stadium screen, a phototherapy device, or a signboard.

According to embodiments, an organometallic compound may be represented by Formula 1:

[Description of Formula 1]

In Formula 1, M may be platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), or osmium (Os). For example, M may be Pt.

In Formula 1, X₁ to X₄ may each independently be a carbon atom (C) or a nitrogen atom (N). In an embodiment, in Formula 1, X₁ may be a carbon atom (C) of a carbene moiety. In an embodiment, in Formula 1, X₂ and X₃ may each be C, and X₄ may be N.

In an embodiment, at least one of X₁ to X₄ may each be N.

In an embodiment, at least two of a bond between M and X₁, a bond between M and X₂, a bond between M and X₃, and a bond between M and X₄ may each be a coordinate bond.

In an embodiment, the bond between M and X₁ may be a coordinate bond. In an embodiment, one of a bond between M and X₂, a bond between M and X₃, and a bond between M and X₄ may be a coordinate bond, and the remaining two thereof may each be a covalent bond.

In an embodiment, the bond between X₂ and M and the bond between X₃ and M may each be a covalent bond, and the bond between X₄ and M may be a coordinate bond.

In an embodiment, X₄ may be N, and the bond between X₄ and M may be a coordinate bond.

In Formula 1, rings CY₁ to CY₄ may each independently be a C₅-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group.

In an embodiment, at least one of rings CY₁ to CY₄ may each include a carbene moiety.

In an embodiment, rings CY₁ to CY₄ may each independently be a benzene group, a naphthalene group, a pyridine group, a pyridazine group, a pyrimidine group, a pyrazine group, a triazine group, a cyclopentadiene group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, a benzoimidazole group, an imidazopyridine group, an imidazopyrimidine group, imidazotriazine group, an imidazopyrazine group, or an imidazopyridazine group.

In an embodiment, rings CY₁ and CY₃ may each independently be a C₄-C₂₀ polycyclic group in which 2 to 4 C₃-C₈ monocyclic groups are condensed with each other. In an embodiment, rings CY₂ and CY₄ may each independently be a C₃-C₈ monocyclic group.

For example, ring CY₁ may be a nitrogen-containing C₁-C₆₀ heterocyclic group.

In an embodiment, in Formula 1, ring CY₁ may be: an X₁-containing 5-membered ring; an X₁-containing 5-membered ring to which at least one 6-membered ring is condensed; or an X₁-containing 6-membered ring. For example, ring CY₁ may include a 5-membered ring that is bonded to M in Formula 1 via X₁. In an embodiment, the X₁-containing 5-membered ring may be a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group, or a thiadiazole group. In an embodiment, the X₁-containing 6-membered ring or a 6-membered ring that may be condensed to the X₁-containing 5-membered ring may each independently be a benzene group, a pyridine group, or a pyrimidine group.

In an embodiment, ring CY₁ may be an X₁-containing 5-membered ring, and the X₁-containing 5-membered ring may be an imidazole group or a triazole group.

In an embodiment, ring CY₁ may be an X₁-containing 5-membered ring to which at least one 6-membered ring is condensed, and the X₁-containing 5-membered ring to which at least one 6-membered ring is condensed may be a benzimidazole group or an imidazopyridine group.

In an embodiment, ring CY₁ may be an imidazole group, a triazole group, a benzimidazole group, a naphthoimidazole group, or an imidazopyridine group.

In an embodiment, X₁ may be C, and ring CY₁ may be an imidazole group, a triazole group, a benzimidazole group, a naphthoimidazole group, or an imidazopyridine group.

In an embodiment, ring CY₂ may be a benzene group, a pyridine group, a pyrimidine group, a naphthalene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a fluorene group, a dibenzosilole group, a naphthobenzofuran group, a naphthobenzothiophene group, a benzocarbazole group, a benzofluorene group, a naphthobenzosilole group, a dinaphthofuran group, a dinaphthothiophene group, a dibenzocarbazole group, a dibenzofluorene group, a dinaphthosilole group, an azadibenzofuran group, an azadibenzothiophene group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azanaphthobenzofuran group, an azanaphthobenzothiophene group, an azabenzocarbazole group, an azabenzofluorene group, an azanaphthobenzosilole group, an azadinaphthofuran group, an azadinaphthothiophene group, an azadibenzocarbazole group, an azadibenzofluorene group, or an azadinaphthosilole group.

In an embodiment, ring CY₂ may be a benzene group, a pyridine group, a pyrimidine group, a naphthalene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a fluorene group, or a dibenzosilole group.

In an embodiment, in Formula 1, ring CY₃ may be: a C₂-C₈ monocyclic group; or a C₄-C₂₀ polycyclic group in which 2 or 3 C₂-C₈ monocyclic groups are condensed with each other.

For example, in Formula 1, ring CY₃ may be: a C₄-C₆ monocyclic group; or a C₄-C₈ polycyclic group in which 2 or 3 C₄-C₆ monocyclic groups are condensed with each other.

The term “C₂-C₈ monocyclic group” as used herein may be a non-condensed ring group, and examples thereof may include a cyclopentadiene group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a cycloheptadiene group, a cyclooctadiene group, or the like.

For example, ring CY₃ may be a benzene group, a pyridine group, a pyrimidine group, a naphthalene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a fluorene group, a dibenzosilole group, an azadibenzofuran group, an azadibenzothiophene group, an azacarbazole group, an azafluorene group, or an azadibenzosilole group.

In an embodiment, in Formula 1, a moiety represented by

may be a moiety represented by Formula A1 or Formula A2:

In Formulae A1 and A2,

• • X₁₂ to X₁₅ may each independently be C or N,
  • * indicates a binding site to M in Formula 1,
  • *′ indicates a binding site to (L₁)_a1 in Formula 1, and
  • *″ indicates a binding site to (L₄)_a4 in Formula 1.

In an embodiment, in Formula 1, a moiety represented by

may be a moiety represented by Formula A3:

In Formula A3,

• • * indicates a binding site to M in Formula 1,
  • *′ indicates a binding site to (L₂)_a2 in Formula 1, and
  • *″ indicates a binding site to (L₃)_a3 in Formula 1.

In Formula 1, L₁ to L₃ may each independently be *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—C(R₅)═*′, *═C(R₅)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₅)—*′,*—N(R₅)—*, *—P(R₅)—*′, *—Si(R₅)(R₆)—*′, *—P(R₅)(R₆)—*′, or *—Ge(R₅)(R₆)—*.

In Formula 1, a1 to a3 may each independently be an integer from 0 to 3.

In Formula 1, when a1 is 0, rings CY₁ and CY₂ may not be linked to each other via (L₁)_a1. In Formula 1, when a1 is 2 or 3, two or three of L₁ may be identical to or different from each other.

In Formula 1, when a2 is 0, rings CY₂ and CY₃ may not be linked to each other via (L₂)_a2. In Formula 1, when a2 is 2 or 3, two or three of L₂ may be identical to or different from each other.

In Formula 1, when a3 is 0, rings CY₃ and CY₄ may not be linked to each other via (L₃)_a3. In Formula 1, when a3 is 2 or 3, two or three of L₃ may be identical to or different from each other.

In Formula 1, L₄ may be a C₅-C₆₀ carbocyclic group unsubstituted or substituted with R_10b or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with R_10b.

In an embodiment, at least one L₄ may each independently be a phenylene group unsubstituted or substituted with R_10b.

In an embodiment, at least one L₄ may each independently be a group represented by one of Formulae 2-1 to 2-3:

In Formulae 2-1 to 2-3,

• • c4 may be an integer from 0 to 4,
  • R_10b may be the same as defined in Formula 1,
  • * indicates a binding site to CY₁ in Formula 1, and
  • *′ indicates a binding site to CY₄ in Formula 1.

In an embodiment, in Formula 1, *-(L₄)_a4-*′ may be a group represented by Formula 2-4:

In Formula 2-4,

• • c4 may be an integer from 0 to 4,
  • R_10b may be the same as defined in Formula 1,
  • * indicates a binding site to CY₁ in Formula 1, and
  • *′ indicates a binding site to CY₄ in Formula 1.

In Formula 1, a4 may be an integer from 1 to 3. For example, CY₁ and CY₄ may be linked to each other via (L₄)_a4. In Formula 1, when a4 is 2 or 3, two or three of L₄ may be identical to or different from each other.

In an embodiment, in Formula 1, a4 may be 2.

In Formula 1, a ring formed by M, X₁-containing CY₁, (L₄)_a4, and X₄-containing CY₄ may be a 9-membered ring. In the specification, the term “ring formed by M, X₁-containing CY₁, (L₄)_a4, and X₄-containing CY₄” may refer to a ring linked in the order of Pt, C, N, C, C, C, C, C, and N in Compound BD6:

In Formula 1, R₁ to R₆ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkenyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkynyl group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ alkoxy group unsubstituted or substituted with at least one R_10a, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, a C₆-C₆₀ aryloxy group unsubstituted or substituted with at least one R_10a, a C₆-C₆₀ arylthio group unsubstituted or substituted with at least one R_10a, a C₇-C₆₀ arylalkyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ heteroarylalkyl group unsubstituted or substituted with at least one R_10a, —C(Q₁)(Q₂)(Q₃), —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂).

In Formula 1, b1 to b4 may each independently be an integer from 0 to 10.

In Formula 1, R_10b and R₁ may optionally be linked to each other to form a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group, and

In Formula 1, R_10b and R₄ may optionally be linked to each other to form a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group.

L₄ may be a C₅-C₆₀ carbocyclic group substituted with at least one R_10b or a C₁-C₆₀ heterocyclic group substituted with R_10b, and in the specification, the term “R_10b and R₁ are linked to each other to form a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group” may refer to a ring linked in the order of N, C, C, C, C, C, C, C, and C of Compound BD6:

In Formula 1, R_10a and R_10b may each independently be:

• • deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;
  • a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₂-C₆₀ heteroarylalkyl group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or any combination thereof;
  • a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, or a C₂-C₆₀ heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₂-C₆₀ heteroarylalkyl group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof; or
  • —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂), and
  • Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently be:
  • hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group; or
  • a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₇-C₆₀ arylalkyl group, or a C₂-C₆₀ heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.

In an embodiment, the organometallic compound may be represented by Formula 1-1 or Formula 1-2:

In Formulae 1-1 and 1-2,

• • X₁₁ and X₄₁ may each independently be C or N, and
  • M, X₁ to X₄, rings CY₁ to CY₄, L₁ to L₄, a1 to a4, R₁ to R₄, and b1 to b4 are the same as defined in Formula 1.

In an embodiment, the organometallic compound may include at least four deuterium atoms.

In an embodiment, the organometallic compound may satisfy at least one of Conditions 1 and 2:

[Condition 1]

At least one of L₄ is substituted with at least four deuterium atoms,

[Condition 2]

In Formula 1, a moiety represented by

is a moiety represented by Formula A3′:

In Formula A3′,

• • R₃₁ is the same as described herein in connection with R₃,
  • c2 may be an integer from 0 to 2,
  • D represents a deuterium atom,
  • * indicates a binding site to M in Formula 1,
  • *′ indicates a binding site to (L₂)_a2 in Formula 1, and
  • *″ indicates a binding site to (L₃)_a3 in Formula 1.

In an embodiment, the organometallic compound may be represented by Formula 3-1 or Formula 3-2:

In Formulae 3-1 and 3-2,

• • X₁, and X₄₁ may each independently be C or N,
  • c3 may be an integer from 0 to 3,
  • c4 may be an integer from 0 to 4,
  • c5 may be an integer from 0 to 5,
  • R_10c may be deuterium, —F, —Cl, —Br, —I, a cyano group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, or a C₁-C₆₀ heterocyclic group,
  • R_10c and R₁ may optionally be linked to each other to form a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group, and
  • M, X₁ to X₄, rings CY₁ to CY₄, L₁ to L₃, a1 to a3, R₁ to R₄, b1 to b4, and R_10b are the same as defined in Formula 1.

In an embodiment, in Formulae 3-1 and 3-2, when R_10c and R₁ are linked to each other, R_10c and R₁ may be linked to each other to form a 9-membered ring.

In an embodiment, in Formula 1, a moiety represented by

may be a moiety represented by one of Formulae 4-1 to 4-3:

In Formulae 4-1 to 4-3,

• • X₁₁ to X₁₆ and X₄₁ to X₄₅ may each independently be C or N,
  • c3 may be an integer from 0 to 3,
  • c4 may be an integer from 0 to 4,
  • c5 may be an integer from 0 to 5,
  • * indicates a binding site to (L₁)_a1 in Formula 1,
  • *′ indicates a binding site to (L₃)_a3 in Formula 1,
  • R_10c may be deuterium, —F, —Cl, —Br, —I, a cyano group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, or a C₁-C₆₀ heterocyclic group, and
  • M, X₁, X₄, R₁, R₄, and R_10b are the same as defined in Formula 1.

[Examples of Compounds]

In an embodiment, the organometallic compound may be one of Compounds BD1 to BD33:

In an embodiment, the second compound may be one of Compounds ETH1 to ETH 100:

In an embodiment, the third compound may be one of Compounds HTH1 to HTH40:

In an embodiment, the fourth compound may be one of Compounds DFD1 to DFD29:

In the Compounds BD1 to BD33, ETH1 to ETH100, HTH1 to HTH40, and DFD1 to DFD29, Ph represents a phenyl group, ^tBu represents a tert-butyl group, and D represents a deuterium atom. For example, a group represented by

may be identical to a group represented by

Since the organometallic compound represented by Formula 1 includes the 9-membered ring formed by M, X₁-containing CY₁, (L₄)_a4, and X₄-containing CY₄, deterioration may be suppressed or prevented, molecular rigidity may be enhanced, and light of a relatively short wavelength may be emitted. The light-emitting device may have improved color purity, improved luminescence efficiency and improved lifespan characteristics due to the inclusion of the organometallic compound.

[Description of FIG. 1]

FIG. 1 is a schematic cross-sectional view of a light-emitting device 10 according to an embodiment. The light-emitting device 10 may include a first electrode 110, an interlayer, and a second electrode 150. The interlayer may include a hole transport region 120, an emission layer 130, and an electron transport region 140.

Hereinafter, the structure of the light-emitting device 10 according to an embodiment and a method of manufacturing the light-emitting device 10 will be described with reference to FIG. 1.

[First Electrode 110]

In FIG. 1, a substrate may be further included under the first electrode 110 or on the second electrode 150. The substrate may be a glass substrate or a plastic substrate. In an embodiment, the substrate may be a flexible substrate. For example, the substrate may include a plastic material with excellent heat resistance and durability, such as polyimide, polyethylene terephthalate (PET), polycarbonate, polyethylene naphthalate, polyarylate (PAR), polyetherimide, or any combination thereof.

The first electrode 110 may be formed by depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, a high-work function material that facilitates hole injection may be used as a material for forming the first electrode 110.

The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode 110 is a transmissive electrode, a material for forming the first electrode 110 may include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), or any combination thereof. When the first electrode 110 is a semi-transmissive electrode or a reflective electrode, a material for forming the first electrode 110 may include magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In ), magnesium-silver (Mg—Ag), or any combination thereof.

The first electrode 110 may have a structure consisting of a single layer or a structure including multiple layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO.

[Interlayer]

An interlayer may be disposed on the first electrode 110. The interlayer may include the emission layer 130.

The interlayer may further include a hole transport region 120 between the first electrode 110 and the emission layer 130, and an electron transport region 140 between the emission layer 130 and the second electrode 150.

The interlayer may further include, in addition to various organic materials, a metal-containing compound such as an organometallic compound, an inorganic material such as a quantum dot, and the like.

In embodiments, the interlayer may include two or more emitting units stacked between the first electrode 110 and the second electrode 150, and at least one charge generation layer which may be each between adjacent units among the two or more emitting units. When the interlayer includes the two or more emitting units and the at least one charge generation layer as described above, the light-emitting device 10 may be a tandem light-emitting device.

[Hole Transport Region 120]

The hole transport region 120 may have a structure consisting of a layer consisting of a single material, a structure consisting of a layer including different materials, or a structure including multiple layers including different materials.

The hole transport region 120 may include a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or any combination thereof.

In embodiments, the hole transport region 120 may have a multi-layered structure including a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole transport layer/emission auxiliary layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, wherein the layers of each structure may be stacked from the first electrode 110 in its respective stated order, but the structure of the hole transport region 120 is not limited thereto.

The hole transport region 120 may include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof:

In Formulae 201 and 202,

• • L₂₀₁ to L₂₀₄ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • L₂₀₅ may be *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a C₁-C₂₀ alkylene group unsubstituted or substituted with at least one R_10a, a C₂-C₂₀ alkenylene group unsubstituted or substituted with at least one R_10a, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • xa1 to xa4 may each independently be an integer from 0 to 5,
  • xa5 may be an integer from 1 to 10,
  • R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • R₂₀₁ and R₂₀₂ may optionally be linked to each other via a single bond, a C₁-C₅ alkylene group unsubstituted or substituted with at least one R_10a, or a C₂-C₅ alkenylene group unsubstituted or substituted with at least one R_10a, to form a C₈-C₆₀ polycyclic group (for example, a carbazole group or the like) unsubstituted or substituted with at least one R_10a (for example, Compound HT16 or the like),
  • R₂₀₃ and R₂₀₄ may optionally be linked to each other via a single bond, a C₁-C₅ alkylene group unsubstituted or substituted with at least one R_10a, or a C₂-C₅ alkenylene group unsubstituted or substituted with at least one R_10a, to form a C₈-C₆₀ polycyclic group unsubstituted or substituted with at least one R_10a, and
  • na1 may be an integer from 1 to 4.

In embodiments, the compound represented by Formula 201 and the compound represented by Formula 202 may each independently include at least one of the groups represented by Formulae CY201 to CY217:

In Formulae CY201 to CY217, R_10b and R_10c may each independently be the same as described herein in connection with R_10a, ring CY₂₀₁ to ring CY₂₀₄ may each independently be a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group, and at least one hydrogen in Formulae CY201 to CY217 may be unsubstituted or substituted with R_10a as described herein.

In an embodiment, in Formulae CY201 to CY217, ring CY₂₀₁ to ring CY₂₀₄ may each independently be a benzene group, a naphthalene group, a phenanthrene group, or an anthracene group.

In embodiments, the compound represented by Formula 201 and the compound represented by Formula 202 may each independently include at least one of the groups represented by Formulae CY201 to CY203.

In embodiments, the compound represented by Formula 201 may include at least one of the groups represented by Formulae CY201 to CY203 and at least one of the groups represented by Formulae CY204 to CY217.

In embodiments, in Formula 201, xa1 may be 1, R₂₀₁ may be a group represented by one of Formulae CY201 to CY203, xa2 may be 0, and R₂₀₂ may be a group represented by one of Formulae CY204 to CY207.

In embodiments, the compound represented by Formula 201 and the compound represented by Formula 202 may each not include the groups represented by Formulae CY201 to CY203.

In embodiments, the compound represented by Formula 201 and the compound represented by Formula 202 may each not include the groups represented by Formulae CY201 to CY203, and may each independently include at least one of the groups represented by Formulae CY204 to CY217.

In embodiments, the compound represented by Formula 201 and the compound represented by Formula 202 may each not include the groups represented by Formulae CY201 to CY217.

In embodiments, the hole transport region 120 may include one of Compounds HT1 to HT46, m-MTDATA, TDATA, 2-TNATA, NPB(NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), or any combination thereof:

A thickness of the hole transport region 120 may be in a range of about 50 Å to about 10,000 Å. For example, the thickness of the hole transport region 120 may be in a range of about 100 Å to about 4,000 Å. When the hole transport region 120 includes a hole injection layer, a hole transport layer, or any combination thereof, a thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, and a thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å. For example, the thickness of the hole injection layer may be in a range of about 100 Å to about 1,000 Å. For example, the thickness of the hole transport layer may be in a range of about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region 120, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer serves to increase light emission efficiency by compensating for an optical resonance distance according to a wavelength of light emitted from the emission layer. The electron blocking layer serves to prevent electron leakage from the emission layer to the hole transport region. Materials that may be included in the hole transport region may be included in the emission auxiliary layer and the electron blocking layer.

[p-dopant]

The hole transport region 120 may include, in addition to the materials as described above, a charge generation material for the improvement of conductivity. The charge generation material may be uniformly or non-uniformly dispersed in the hole transport region (for example, in the form of a single layer consisting of a charge generation material).

The charge generation material may be, for example, a p-dopant.

In an embodiment, the p-dopant may have a lowest unoccupied molecular orbital (LUMO) energy level of equal to or less than about −3.5 eV.

In an embodiment, the p-dopant may include a quinone derivative, a cyano group-containing compound, a compound including element EL1 and element EL2, or any combination thereof.

Examples of a quinone derivative may include TCNQ, F4-TCNQ, and the like.

Examples of a cyano group-containing compound may include HAT-CN, a compound represented by Formula 221, and the like:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, and

at least one of R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, each substituted with: a cyano group; —F; —Cl; —Br; —I; a C₁-C₂₀ alkyl group substituted with a cyano group, —F, —Cl, —Br, —I, or any combination thereof; or any combination thereof.

In the compound including element EL1 and element EL2, element EL1 may be a metal, a metalloid, or any combination thereof, and element EL2 may be a non-metal, a metalloid, or any combination thereof.

Examples of a metal may include: an alkali metal (for example, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), or the like); an alkaline earth metal (for example, beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), or the like); a transition metal (for example, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), or the like); a post-transition metal (for example, zinc (Zn), indium (In), tin (Sn), or the like); a lanthanide metal (for example, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or the like); and the like.

Examples of a metalloid may include silicon (Si), antimony (Sb), tellurium (Te), and the like.

Examples of a non-metal may include oxygen (O), a halogen (for example, F, Cl, Br, I, or the like), and the like.

Examples of a compound containing element EL1 and element EL2 may include a metal oxide, a metal halide (for example, a metal fluoride, a metal chloride, a metal bromide, a metal iodide, or the like), a metalloid halide (for example, a metalloid fluoride, a metalloid chloride, a metalloid bromide, a metalloid iodide, or the like), a metal telluride, or any combination thereof.

Examples of a metal oxide may include a tungsten oxide (for example, WO, W₂O₃, WO₂, WO₃, W₂O₅, or the like), a vanadium oxide (for example, VO, V₂O₃, VO₂, V₂O₅, or the like), a molybdenum oxide (for example, MoO, Mo₂O₃, MoO₂, MoO₃, Mo₂O₅, or the like), a rhenium oxide (for example, ReO₃ or the like), and the like.

Examples of a metal halide may include an alkali metal halide, an alkaline earth metal halide, a transition metal halide, a post-transition metal halide, a lanthanide metal halide, and the like.

Examples of an alkali metal halide may include LiF, NaF, KF, RbF, CsF, LiCl, NaCl, KCl, RbCI, CsCl, LiBr, NaBr, KBr, RbBr, CsBr, LiI, NaI, KI, RbI, CsI, and the like.

Examples of an alkaline earth metal halide may include BeF₂, MgF₂, CaF₂, SrF₂, BaF₂, BeCl₂, MgCl₂, CaCl₂, SrCl₂, BaCl₂, BeBr₂, MgBr₂, CaBr₂, SrBr₂, BaBr₂, BeI₂, MgI₂, CaI₂, SrI₂, BaI₂, and the like.

Examples of a transition metal halide may include a titanium halide (for example, TiF₄, TiCl₄, TiBr₄, TiI₄, or the like), a zirconium halide (for example, ZrF₄, ZrCl₄, ZrBr₄, ZrI₄, or the like), a hafnium halide (for example, HfF₄, HfCl₄, HfBr₄, HfI₄, or the like), a vanadium halide (for example, VF₃, VCl₃, VBr₃, VI₃, or the like), a niobium halide (for example, NbF₃, NbCl₃, NbBr₃, NbI₃, or the like), a tantalum halide (for example, TaF₃, TaCl₃, TaBr₃, TaI₃, or the like), a chromium halide (for example, CrF₃, CrCl₃, CrBr₃, CrI₃, or the like), a molybdenum halide (for example, MoF₃, MoCl₃, MoBr₃, MoI₃, or the like), a tungsten halide (for example, WF₃, WCl₃, WBr₃, WI₃, or the like), a manganese halide (for example, MnF₂, MnCl₂, MnBr₂, MnI₂, or the like), a technetium halide (for example, TcF₂, TcCl₂, TcBr₂, TcI₂, or the like), a rhenium halide (for example, ReF₂, ReCl₂, ReBr₂, ReI₂, or the like), an iron halide (for example, FeF₂, FeCl₂, FeBr₂, FeI₂, or the like), a ruthenium halide (for example, RuF₂, RuCl₂, RuBr₂, RuI₂, or the like), an osmium halide (for example, OsF₂, OSCl₂, OsBr₂, OsI₂, or the like), a cobalt halide (for example, CoF₂, CoCl₂, CoBr₂, CoI₂, or the like), a rhodium halide (for example, RhF₂, RhCl₂, RhBr₂, RhI₂, or the like), an iridium halide (for example, IrF₂, IrCl₂, IrBr₂, IrI₂, or the like), a nickel halide (for example, NiF₂, NiCl₂, NiBr₂, NiI₂, or the like), a palladium halide (for example, PdF₂, PdCl₂, PdBr₂, PdI₂, or the like), a platinum halide (for example, PtF₂, PtCl₂, PtBr₂, PtI₂, or the like), a copper halide (for example, CuF, CuCl, CuBr, CuI, or the like), a silver halide (for example, AgF, AgCl, AgBr, AgI, or the like), a gold halide (for example, AuF, AuCl, AuBr, AuI, or the like), and the like.

Examples of a post-transition metal halide may include a zinc halide (for example, ZnF₂, ZnCl₂, ZnBr₂, ZnI₂, or the like), an indium halide (for example, InI₃ or the like), a tin halide (for example, SnI₂ or the like), and the like.

Examples of a lanthanide metal halide may include YbF, YbF₂, YbF₃, SmF₃, YbCl, YbCl₂, YbCl₃ SmCl₃, YbBr, YbBr₂, YbBr₃, SmBr₃, YbI, YbI₂, YbI₃, SmI₃, and the like.

Examples of a metalloid halide may include an antimony halide (for example, SbCl₅ or the like) and the like.

Examples of a metal telluride may include an alkali metal telluride (for example, Li₂Te, Na₂Te, K₂Te, Rb₂Te, Cs₂Te, or the like), an alkaline earth metal telluride (for example, BeTe, MgTe, CaTe, SrTe, BaTe, and the like), a transition metal telluride (for example, TiTe₂, ZrTe₂, HfTe₂, V₂Te₃, Nb₂Te₃, Ta₂Te₃, Cr₂Te₃, Mo₂Te₃, W₂Te₃, MnTe, TcTe, ReTe, FeTe, RuTe, OsTe, CoTe, RhTe, IrTe, NiTe, PdTe, PtTe, Cu₂Te, CuTe, Ag₂Te, AgTe, Au₂Te, or the like), a post-transition metal telluride (for example, ZnTe or the like), and a lanthanide metal telluride (for example, LaTe, CeTe, PrTe, NdTe, PmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, or the like).

[Emission Layer 130]

When the light-emitting device 10 is a full-color light-emitting device, the emission layer 130 may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer, according to a subpixel. In embodiments, the emission layer 130 may have a stacked structure of two or more layers of a red emission layer, a green emission layer, and a blue emission layer, in which the two or more layers may contact each other or may be separated from each other, to emit white light. In embodiments, the emission layer 130 may include two or more materials of a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials may be mixed with each other in a single layer, to emit white light.

The emission layer 130 may include a host and a dopant. The dopant may include a phosphorescent dopant, a fluorescent dopant, or any combination thereof.

An amount of the dopant in the emission layer 130 may be in a range of about 0.01 parts by weight to about 15 parts by weight, with respect to 100 parts by weight of the host.

In embodiments, the emission layer 130 may include a quantum dot.

In embodiments, the emission layer 130 may include a delayed fluorescence material. The delayed fluorescence material may serve as a host or as a dopant in the emission layer.

A thickness of the emission layer 130 may be in a range of about 100 Å to about 1,000 Å. For example, the thickness of the emission layer 130 may be in a range of about 200 Å to about 600 Å. When the thickness of the emission layer 130 is within any of these ranges, excellent luminescence characteristics may be obtained without a substantial increase in driving voltage.

[Host]

In embodiments, the host may include a compound represented by Formula 301:

$\begin{array}{cc}{\left[{\mathrm{Ar}}_{301}\right]}_{\mathrm{xb}11}-{\left[{\left(L_{301}\right)}_{\mathrm{xb}1}-R_{301}\right]}_{\mathrm{xb}21}& \left[\mathrm{Formula}301\right]\end{array}$

In Formula 301,

• • Ar₃₀₁ and L₃₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • xb11 may be 1, 2, or 3,
  • xb1 may be an integer from 0 to 5,
  • R₃₀₁ may be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkenyl group unsubstituted or substituted with at least one R_10a, a C₂-C₆₀ alkynyl group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ alkoxy group unsubstituted or substituted with at least one R_10a, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), or —P(═O)(Q₃₀₁)(Q₃₀₂),
  • xb21 may be an integer from 1 to 5, and
  • Q₃₀₁ to Q₃₀₃ may each independently be the same as described herein in connection with Q₁.

In an embodiment, in Formula 301, when xb11 is 2 or more, two or more of Ar₃₀₁ may be linked to each other via a single bond.

In embodiments, the host may include a compound represented by Formula 301-1, a compound represented by Formula 301-2, or any combination thereof:

In Formulae 301-1 and 301-2,

• • ring A₃₀₁ to ring A₃₀₄ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • X₃₀₁ may be O, S, N[(L₃₀₄)_xb4-R₃₀₄], C(R₃₀₄)(R₃₀₅), or Si(R₃04)(R₃₀₅),
  • xb22 and xb23 may each independently be 0, 1, or 2,
  • L₃₀₁, xb1, and R₃₀₁ may each be the same as described herein,
  • L₃₀₂ to L₃₀₄ may each independently be the same as described in connection with L₃₀₁,
  • xb2 to xb4 may each independently be the same as described in connection with xb1, and
  • R₃₀₂ to R₃₀₅ and R₃₁₁ to R₃₁₄ may each independently be the same as described in connection with R₃₀₁.

In embodiments, the host may include an alkali earth metal complex, a post-transition metal complex, or any combination thereof. For example, the host may include a Be complex (for example, Compound H55), an Mg complex, a Zn complex, or any combination thereof.

In embodiments, the host may include one of Compounds H1 to H128, 9,10-di(2-naphthyl)anthracene (ADN), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), 9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di(carbazol-9-yl)benzene (mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), or any combination thereof:

[Phosphorescent Dopant]

The phosphorescent dopant may include at least one transition metal as a core metal.

The phosphorescent dopant may include a monodentate ligand, a bidentate ligand, a tridentate ligand, a tetradentate ligand, a pentadentate ligand, a hexadentate ligand, or any combination thereof.

The phosphorescent dopant may be electrically neutral.

In an embodiment, the phosphorescent dopant may include an organometallic compound represented by Formula 401:

In Formulae 401 and 402,

• • M may be a transition metal (for example, iridium (Ir), platinum (Pt), palladium (Pd), osmium (Os), titanium (Ti), gold (Au), hafnium (Hf), europium (Eu), terbium (Tb), rhodium (Rh), rhenium (Re), or thulium (Tm)),
  • L₄₀₁ may be a ligand represented by Formula 402, and xc1 may be 1, 2, or 3, wherein when xc1 is 2 or more, two or more of L₄₀₁ may be identical to or different from each other,
  • L₄₀₂ may be an organic ligand, and xc2 may be 0, 1, 2, 3, or 4, wherein when xc2 is 2 or more, two or more of L₄₀₂ may be identical to or different from each other,
  • X₄₀₁ and X₄₀₂ may each independently be N or C, rings A₄₀₁ and A₄₀₂ may each independently be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,
  • T₄₀₁ may be a single bond, *—O—*′, *—S*′, *—C(═O)—*′, *—N(Q₄₁₁)—*′, *—C(Q₄₁₁)(Q₄₁₂)—*′, *—C(Q₄₁₁)═C(Q₄₁₂)—*′, *—C(Q₄₁₁)═*′, or *═C═*′,
  • X₄₀₃ and X₄₀₄ may each independently be a chemical bond (for example, a covalent bond or a coordination bond), O, S, N(Q₄₁₃), B(Q₄₁₃), P(Q₄₁₃), C(Q₄₁₃)(Q₄₁₄), or Si(Q₄₁₃)(Q₄₁₄),
  • Q₄₁₁ to Q₄₁₄ may each independently be the same as described in connection with Q₁,
  • R₄₀₁ and R₄₀₂ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkyl group unsubstituted or substituted with at least one R_10a, a C₁-C₂₀ alkoxy group unsubstituted or substituted with at least one R_10a, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), or —P(═O)(Q₄₀₁)(Q₄₀₂),
  • Q₄₀₁ to Q₄₀₃ may each independently be the same as described in connection with Q₁,
  • xc11 and xc12 may each independently be an integer from 0 to 10, and
  • and *′ in Formula 402 each indicate a binding site to M in Formula 401.

In an embodiment, in Formula 402, X₄₀₁ may be nitrogen and X₄₀₂ may be carbon, or X₄₀₁ and X₄₀₂ may each be nitrogen.

In embodiments, in Formula 401, when xc1 is 2 or more, two ring A₄₀₁ (s) among two or more of L₄₀₁ may optionally be linked to each other via T₄₀₂, which is a linking group, and two ring A₄₀₂ (s) among two or more of L₄₀₁ may optionally be linked to each other via T₄₀₃, which is a linking group (see Compounds PD1 to PD4 and PD7). T₄₀₂ and T₄₀₃ may each independently be the same as described in connection with T₄₀₁.

In Formula 401, L₄₀₂ may be an organic ligand. For example, L₄₀₂ may include a halogen group, a diketone group (for example, an acetylacetonate group), a carboxylic acid group (for example, a picolinate group), —C(═O), an isonitrile group, a —CN group, a phosphorus group (for example, a phosphine group, a phosphite group, or the like), or any combination thereof.

In an embodiment, the phosphorescent dopant may include, for example, one of Compounds PD1 to PD39, or any combination thereof:

[Fluorescent Dopant]

The fluorescent dopant may include an amine group-containing compound, a styryl group-containing compound, or any combination thereof.

In an embodiment, the fluorescent dopant may include a compound represented by Formula 501:

In Formula 501,

• • Ar₅₀₁, L₅₀₁ to L₅₀₃, R₅₀₁, and R₅₀₂ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • xd1 to xd3 may each independently be 0, 1, 2, or 3, and
  • xd4 may be 1, 2, 3, 4, 5, or 6.
  • In an embodiment, in Formula 501, Ar₅₀₁ may be a condensed cyclic group (for example, an anthracene group, a chrysene group, a pyrene group, or the like) in which three or more monocyclic groups are condensed together.

In embodiments, in Formula 501, xd4 may be 2.

In an embodiment, the fluorescent dopant may include one of Compounds FD1 to FD37, DPVBi, DPAVBi, or any combination thereof:

[Delayed Fluorescence Material]

The emission layer 130 may include a delayed fluorescence material.

In the specification, the delayed fluorescence material may be selected from compounds capable of emitting delayed fluorescence, based on a delayed fluorescence emission mechanism.

The delayed fluorescence material included in the emission layer 130 may serve as a host or as a dopant, depending on the types of other materials included in the emission layer 130.

In an embodiment, a difference between a triplet energy level (eV) of the delayed fluorescence material and a singlet energy level (eV) of the delayed fluorescence material may be in a range of about 0 eV to about 0.5 eV. When the difference between a triplet energy level (eV) of the delayed fluorescence material and a singlet energy level (eV) of the delayed fluorescence material is within the above range, up-conversion from a triplet state to a singlet state of the delayed fluorescence material may effectively occur, and thus, the light-emitting device 10 may have improved luminescence efficiency.

In embodiment, the delayed fluorescence material may include: a material including at least one electron donor (for example, a π electron-rich C₃-C₆₀ cyclic group and the like, such as a carbazole group) and at least one electron acceptor (for example, a sulfoxide group, a cyano group, a π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group, and the like); a material including a C₈-C₆₀ polycyclic group including at least two cyclic groups condensed to each other while sharing boron (B); or the like.

Examples of a delayed fluorescence material may include at least one of Compounds DF1 to DF14:

[Quantum Dots]

The emission layer 130 may include quantum dots.

In the specification, a quantum dot may be a crystal of a semiconductor compound. Quantum dots are capable of emitting light of various emission wavelengths according to a size of the crystal. Quantum dots may also emit light of various emission wavelengths by adjusting a ratio of atoms constituting the quantum dots.

A diameter of the quantum dot may be, for example, in a range of about 1 nm to about 10 nm.

The quantum dots may be synthesized by a wet chemical process, a metal organic chemical vapor deposition process, a molecular beam epitaxy process, or any similar process.

The wet chemical process is a method in which an organic solvent and a precursor material are mixed, and a quantum dot particle crystal is grown. When the crystal grows, the organic solvent naturally serves as a dispersant coordinated on the surface of the quantum dot crystal and may control the growth of the crystal, and thus, the wet chemical method may be more readily performed than vapor deposition methods, such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), and the growth of quantum dot particles may be controlled through a low-cost process.

The quantum dot may include a Group II-VI semiconductor compound, a Group III-V semiconductor compound, a Group III-VI semiconductor compound, a Group I-III-VI semiconductor compound, a Group IV-VI semiconductor compound, a Group IV element or compound, or any combination thereof.

Examples of a Group II-VI semiconductor compound may include: a binary compound, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or the like; a ternary compound, such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or the like; a quaternary compound, such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or the like; or any combination thereof.

Examples of a Group III-V semiconductor compound may include: a binary compound, such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or the like; a ternary compound, such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, InPSb, or the like; a quaternary compound, such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or the like; or any combination thereof. In embodiments, the Group III-V semiconductor compound may further include a Group II element. Examples of a Group III-V semiconductor compound further including a Group II element may include InZnP, InGaZnP, InAlZnP, and the like.

Examples of a Group III-VI semiconductor compound may include: a binary compound, such as GaS, Ga₂S₃, GaSe, Ga₂Se₃, GaTe, InS, InSe, In₂Se₃, InTe, or the like; a ternary compound, such as InGaS₃, InGaSe₃, or the like; or any combination thereof.

Examples of a Group I-III-VI semiconductor compound may include: a ternary compound, such as AgInS, AgInS₂, AgInSe₂, AgGaS, AgGaS₂, AgGaSe₂, CuInS, CuInS₂, CuInSe₂, CuGaS₂, CuGASe₂, CuGaO₂, AgGaO₂, AgAlO₂, or the like; a quaternary compound such as AgInGaS₂, AgInGaSe₂, or the like; or any combination thereof.

Examples of a Group IV-VI semiconductor compound may include: a binary compound, such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or the like; a ternary compound, such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or the like; a quaternary compound, such as SnPbSSe, SnPbSeTe, SnPbSTe, or the like; or any combination thereof.

Examples of a Group IV element or compound may include: a single element, such as Si, Ge, or the like; a binary compound, such as SiC, SiGe, or the like; or any combination thereof.

Each element included in a multi-element compound, such as a binary compound, a ternary compound, or a quaternary compound, may be present in a particle at a uniform concentration or at a non-uniform concentration. For example, a formula may represent the types of elements included in a compound, and an atomic ratio in the compound may be different. For example, AgInGaS₂ may indicate AgIn_xGa_1-xS₂ (wherein x may be a real number from 0 to 1).

In embodiments, the quantum dot may have a single structure in which the concentration of each element in the quantum dot is uniform, or the quantum dot may have a core-shell structure. In an embodiment, in case that the quantum dot has a core-shell structure, a material included in the core and a material included in the shell may be different from each other.

The shell of the quantum dot may serve as a protective layer that prevents chemical denaturation of the core to maintain semiconductor characteristics, and/or may serve as a charging layer that imparts electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multi-layer. An interface between the core and the shell may have a concentration gradient in which the concentration of an element that is present in the shell decreases toward the core.

Examples of a shell of a quantum dot may include a metal oxide, a non-metal oxide, a semiconductor compound, or any combination thereof. Examples of a metal oxide or a non-metal oxide may include: a binary compound, such as SiO₂, Al₂O₃, TiO₂, ZnO, MnO, Mn₂O₃, Mn₃O₄, CuO, FeO, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄, or NiO; a ternary compound, such as MgAl₂O₄, CoFe₂O₄, NiFe₂O₄, or CoMn₂O₄; and any combination thereof.

Examples of a semiconductor compound may include, as described herein, a Group III-VI semiconductor compound, a Group II-VI semiconductor compound, a Group III-V semiconductor compound, a Group III-VI semiconductor compound, a Group I-III-VI semiconductor compound, a Group IV-VI semiconductor compound, or any combination thereof. Examples of a semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaS, GaSe, AgGaS, AgGaS₂, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or any combination thereof.

The quantum dot may have a full width at half maximum (FWHM) of an emission wavelength spectrum equal to or less than about 45 nm. For example, the quantum dot may have a FWHM of an emission wavelength spectrum equal to or less than about 40 nm. For example, the quantum dot may have a FWHM of an emission wavelength spectrum equal to or less than about 30 nm. When the FWHM of the quantum dot is within any of these ranges, the quantum dot may have improved color purity or improved color reproducibility. Light emitted through a quantum dot may be emitted in all directions, so that an optical viewing angle may be improved.

In embodiments, the quantum dot may be, for example, in the form of a spherical particle, a pyramidal particle, a multi-arm particle, a cubic nanoparticle, a nanotube particle, a nanowire particle, a nanofiber particle, or a nanoplate particle.

By adjusting the size of the quantum dot or an atomic ratio in a compound of the quantum dot, the energy band gap may be adjusted, and thus, light of various wavelengths may be obtained from a quantum dot emission layer. Thus, by using the above-described quantum dots (by using quantum dots with different sizes or by varying an atomic ratio in a compound of the quantum dot), a light-emitting device that emits light of various wavelengths may be achieved. In embodiments, the size of the quantum dot or the adjustment of the atomic ratio in a compound of the quantum dot may be selected such that the quantum dot can emit red light, green light, and/or blue light. In an embodiment, the quantum dots may be configured to emit white light by a combination of light of various colors.

[Electron Transport Region 140]

The electron transport region 140 may have a structure consisting of a layer consisting of a single material, a structure consisting of a layer including different materials, or a multi-layered structure including multiple layers including different materials.

The electron transport region 140 may include a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or any combination thereof.

In embodiments, the electron transport region may have an electron transport layer/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, wherein the layers of each structure may be stacked from an emission layer 130 in its respective stated order, but the structure of the electron transport region 140 is not limited thereto.

The electron transport region 140 (for example, a buffer layer, a hole blocking layer, an electron control layer, or an electron transport layer in the electron transport region 140) may include a metal-free compound including at least one π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group.

In an embodiment, the electron transport region 140 may include a compound represented by Formula 601:

$\begin{array}{cc}{\left[{\mathrm{Ar}}_{601}\right]}_{\mathrm{xe}11}-{\left[{\left(L_{601}\right)}_{\mathrm{xe}1}-R_{601}\right]}_{\mathrm{xe}21}& \left[\mathrm{Formula}601\right]\end{array}$

In Formula 601,

• • Ar₆₀₁ and L₆₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a,
  • xe11 may be 1, 2, or 3,
  • xe1 may be 0, 1, 2, 3, 4, or 5,
  • R₆₀₁ may be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), or —P(═O)(Q₆₀₁)(Q₆₀₂),
  • Q₆₀₁ to Q₆₀₃ may each independently be the same as described herein in connection with Q₁,
  • xe21 may be 1, 2, 3, 4, or 5, and
  • at least one of Ar₆₀₁, L₆₀₁, and R₆₀₁ may each independently be a π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group unsubstituted or substituted with at least one R_10a.

In an embodiment, in Formula 601, when xe11 is 2 or more, two or more of Ar₆₀₁ may be linked to each other via a single bond.

In embodiments, in Formula 601, Ar₆₀₁ may be an anthracene group unsubstituted or substituted with at least one R_10a.

In embodiments, the electron transport region 140 may include a compound represented by Formula 601-1:

In Formula 601-1,

• • X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N or C(R₆₁₆), and at least one of X₆₁₄ to X₆₁₆ may each be N,
  • L₆₁₁ to L₆₁₃ may each independently be the same as described in connection with L₆₀₁,
  • xe611 to xe613 may each independently be the same as described in connection with xe1,
  • R₆₁₁ to R₆₁₃ may each independently be the same as described in connection with R₆₀₁, and
  • R₆₁₄ to R₆₁₆ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_10a, or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_10a.

In embodiments, in Formulae 601 and 601-1, xe1 and xe611 to xe613 may each independently be 0, 1, or 2.

The electron transport region 140 may include one of Compounds ET1 to ET45, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq, TAZ, NTAZ, or any combination thereof:

A thickness of the electron transport region 140 may be in a range of about 100 Å to about 5,000 Å. For example, the thickness of the electron transport region 140 may be in a range of about 160 Å to about 4,000 Å. When the electron transport region includes a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, or any combination thereof, a thickness of the buffer layer, the hole blocking layer, or the electron control layer may each independently be in a range of about 20 Å to about 1,000 Å, and a thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å. For example, the thickness of the buffer layer, the hole blocking layer, or the electron control layer may each independently be in a range of about 30 Å to about 300 Å. For example, the thickness of the electron transport layer may be in a range of about 150 Å to about 500 Å. When the thicknesses of the buffer layer, the hole blocking layer, the electron control layer, the electron transport layer, and/or the electron transport region 140 are within these ranges, satisfactory electron transporting characteristics may be obtained without a substantial increase in driving voltage.

The electron transport region 140 (for example, an electron transport layer in the electron transport region 140) may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include an alkali metal complex, an alkaline earth metal complex, or any combination thereof. A metal ion of an alkali metal complex may be a Li ion, a Na ion, a K ion, a Rb ion, or a Cs ion, and a metal ion of an alkaline earth metal complex may be a Be ion, an Mg ion, a Ca ion, a Sr ion, or a Ba ion.

A ligand coordinated with a metal ion of the alkali metal complex or a metal ion of the alkaline earth-metal complex may each independently include a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxyphenyloxadiazole, a hydroxyphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenylbenzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or any combination thereof.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (LiQ) or Compound ET-D2:

The electron transport region 140 may include an electron injection layer that facilitates the injection of electrons from the second electrode 150. The electron injection layer may directly contact the second electrode 150.

The electron injection layer may have a structure consisting of a layer consisting of a single material, a structure consisting of a layer including different materials, or a structure including multiple layers including different materials.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or any combination thereof.

The alkali metal may include Li, Na, K, Rb, Cs, or any combination thereof. The alkaline earth metal may include Mg, Ca, Sr, Ba, or any combination thereof. The rare earth metal may include Sc, Y, Ce, Tb, Yb, Gd, or any combination thereof.

The alkali metal-containing compound, the alkaline earth metal-containing compound, and the rare earth metal-containing compound may be oxides, halides (for example, fluorides, chlorides, bromides, or iodides), tellurides, or any combination thereof of each of the alkali metal, the alkaline earth metal, and the rare earth metal.

The alkali metal-containing compound may include: an alkali metal oxide, such as Li₂O, Cs₂O, K₂O, or the like; an alkali metal halide, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, KI, or the like; or any combination thereof. The alkaline earth metal-containing compound may include an alkaline earth metal compound, such as BaO, SrO, CaO, Ba_xSr_1-xO (wherein x is a real number satisfying 0<x<1), Ba_xCa_1-xO (wherein x is a real number satisfying 0<x<1), or the like. The rare earth metal-containing compound may include YbF₃, ScF₃, Sc₂O₃, Y₂O₃, Ce₂O₃, GdF₃, TbF₃, YbI₃, ScI₃, TbI₃, or any combination thereof. In embodiments, the rare earth metal-containing compound may include a lanthanide metal telluride. Examples of a lanthanide metal telluride may include LaTe, CeTe, PrTe, NdTe, PmTe, SmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, La₂Te₃, Ce₂Te₃, Pr₂Te₃, Nd₂Te₃, Pm₂Te₃, Sm₂Te₃, Eu₂Te₃, Gd₂Te₃, Tb₂Te₃, Dy₂Te₃, Ho₂Te₃, Er₂Te₃, Tm₂Te₃, Yb₂Te₃, Lu₂Te₃, and the like.

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include: an alkali metal ion, an alkaline earth metal ion, or a rare earth metal ion; and a ligand bonded to the metal ion (for example, a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxyphenyloxadiazole, a hydroxyphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenyl benzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or any combination thereof).

The electron injection layer may consist of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or any combination thereof, as described above. In embodiments, the electron injection layer may further include an organic material (for example, a compound represented by Formula 601).

In an embodiment, the electron injection layer may consist of an alkali metal-containing compound (for example, alkali metal halide); or the electron injection layer may consist of an alkali metal-containing compound (for example, an alkali metal halide), and an alkali metal, an alkaline earth metal, a rare earth metal, or any combination thereof. For example, the electron injection layer may be a KI:Yb co-deposited layer, an RbI:Yb co-deposited layer, a LiF:Yb co-deposited layer, or the like.

When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof may be uniformly or non-uniformly dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å. For example, the thickness of the electron injection layer may be in a range of about 3 Å to about 90 Å. When the thickness of the electron injection layer is within any of these ranges, satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.

[Second Electrode 150]

The second electrode 150 may be disposed on the electron transport region 140. The second electrode 150 may be a cathode, which is an electron injection electrode. When the second electrode 150 is a cathode, a material for forming the second electrode 150 may include a material having a low work function, such as a metal, an alloy, an electrically conductive compound, or any combination thereof.

The second electrode 150 may include lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ytterbium (Yb), silver-ytterbium (Ag—Yb), ITO, IZO, or any combination thereof. The second electrode 150 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 150 may have a single-layered structure or a multi-layered structure.

[Capping Layer]

The light-emitting device 10 may include a first capping layer outside the first electrode 110, and/or a second capping layer outside the second electrode 150. In embodiments, the light-emitting device 10 may have a structure in which the first capping layer, the first electrode 110, the interlayer, and the second electrode 150 are stacked in the stated order, a structure in which the first electrode 110, the interlayer, the second electrode 150, and the second capping layer are stacked in the stated order, or a structure in which the first capping layer, the first electrode 110, the interlayer, the second electrode 150, and the second capping layer are stacked in the stated order.

Light generated in the emission layer 130 of the light-emitting device 10 may pass through the first electrode 110, which may be a semi-transmissive electrode or a transmissive electrode, and through the first capping layer to the outside. Light generated in the emission layer 130 of the light-emitting device 10 may pass through the second electrode 150, which may be a semi-transmissive electrode or a transmissive electrode, and through the second capping layer to the outside.

The first capping layer and the second capping layer may each increase external luminescence efficiency based on the principle of constructive interference. Accordingly, the optical extraction efficiency of the light-emitting device 10 may be increased, thus improving the luminescence efficiency of the light-emitting device 10.

The first capping layer and the second capping layer may each include a material having a refractive index equal to or greater than about 1.2 (with respect to a wavelength of about 461 nm).

The first capping layer and the second capping layer may each independently be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, or an organic-inorganic composite capping layer including an organic material and an inorganic material.

At least one of the first capping layer and the second capping layer may each independently include a carbocyclic compound, a heterocyclic compound, an amine group-containing compound, a porphine derivative, a phthalocyanine derivative, a naphthalocyanine derivative, an alkali metal complex, an alkaline earth metal complex, or any combination thereof. The carbocyclic compound, the heterocyclic compound, and the amine group-containing compound may optionally be substituted with a substituent including O, N, S, Se, Si, F, Cl, Br, I, or any combination thereof.

In an embodiment, at least one of the first capping layer and the second capping layer may each independently include an amine group-containing compound.

In embodiments, at least one of the first capping layer and the second capping layer may each independently include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof.

In embodiments, at least one of the first capping layer and the second capping layer may each independently include one of Compounds HT28 to HT33, one of Compounds CP1 to CP6, β-NPB, or any combination thereof:

[Film]

The organometallic compound represented by Formula 1 may be included in various films. Accordingly, embodiments provide a film that includes the organometallic compound represented by Formula 1. The film may be, for example, an optical member (or a light control means) (for example, a color filter, a color conversion member, a capping layer, a light extraction efficiency enhancement layer, a selective light absorbing layer, a polarizing layer, a quantum dot-containing layer, or like), a light-shielding member (for example, a light reflective layer, a light absorbing layer, or the like), or a protective member (for example, an insulating layer, a dielectric layer, or the like).

[Electronic Device]

The light-emitting device may be included in various electronic devices. For example, an electronic device including the light-emitting device may be a display device, an authentication device, or the like.

The electronic device (e.g., a display device) may further include, in addition to the light-emitting device, a color filter, a color conversion layer, or a color filter and a color conversion layer. The color filter and/or the color conversion layer may be arranged in at least one traveling direction of light emitted from the light-emitting device. For example, the light emitted from the light-emitting device may be blue light or white light. The light-emitting device may be a light-emitting device as described herein. In an embodiment, the color conversion layer may include a quantum dot. The quantum dot may be, for example, a quantum dot as described herein.

The electronic device may include a first substrate. The first substrate may include subpixels, the color filter may include color filter areas respectively corresponding to the subpixels, and the color conversion layer may include color conversion areas respectively corresponding to the subpixels.

A pixel-defining film may be arranged between the subpixels to define each subpixel.

The color filter may further include color filter areas and light-shielding patterns arranged between the color filter areas, and the color conversion layer may further include color conversion areas and light-shielding patterns arranged between the color conversion areas.

The color filter areas (or the color conversion areas) may include: a first area emitting first color light; a second area emitting second color light; and/or a third area emitting third color light, in which the first color light, the second color light, and/or the third color light may have different maximum emission wavelengths. For example, the first color light may be red light, the second color light may be green light, and the third color light may be blue light. In an embodiment, the color filter areas (or the color conversion areas) may include quantum dots. In embodiments, the first area may include red quantum dots, the second area may include green quantum dots, and the third area may not include a quantum dot. The quantum dot may be a quantum dot as described herein. The first area, the second area, and/or the third area may each further include a scatterer.

In an embodiment, the light-emitting device may emit first light, the first area may absorb the first light to emit first-first color light, the second area may absorb the first light to emit second-first color light, and the third area may absorb the first light to emit third-first color light. In this regard, the first-first color light, the second-first color light, and the third-first color light may have different maximum emission wavelengths. In embodiments, the first light may be blue light, the first-first color light may be red light, the second-first color light may be green light, and the third-first color light may be blue light.

The electronic device may further include a thin-film transistor, in addition to the light-emitting device as described above. The thin-film transistor may include a source electrode, a drain electrode, and an active layer, in which any one of the source electrode and the drain electrode may be electrically connected to any one of the first electrode and the second electrode of the light-emitting device.

The thin-film transistor may further include a gate electrode, a gate insulating film, or the like.

The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor, an oxide semiconductor, or the like.

The electronic device may further include an encapsulation unit for encapsulating the light-emitting device. The encapsulation unit may be arranged between the color filter and/or the color conversion layer and the light-emitting device. The encapsulation unit may allow light to pass to the outside from the light-emitting device and may prevent air and moisture from permeating into the light-emitting device at the same time. The encapsulation unit may be an encapsulation substrate including a transparent glass substrate or a plastic substrate. The encapsulation unit may be a thin-film encapsulation layer including at least one of an organic layer and an inorganic layer. When the encapsulation unit is a thin-film encapsulation layer, the electronic device may be flexible.

In addition to the color filter and/or the color conversion layer, various functional layers may be further disposed on the encapsulation unit, depending on the use of the electronic device. Examples of a functional layer may include a touch screen layer, a polarizing layer, and the like. The touch screen layer may be a resistive touch screen layer, a capacitive touch screen layer, or an infrared touch screen layer. The authentication device may be, for example, a biometric authentication device that authenticates an individual by using biometric information of a living body (for example, a fingertip, a pupil, or the like).

The authentication device may further include, in addition to the light-emitting device as described above, a biometric information collector.

The electronic device may be applied to various displays, an optical source, lighting, a personal computer (e.g., a mobile personal computer), a mobile phone, a digital camera, an electronic note, an electronic dictionary, an electronic game console, a medical device (e.g., an electronic thermometer, a blood pressure meter, a glucometer, a pulse measurement device, a pulse wave measuring device, an electrocardiogram recorder, an ultrasonic diagnostic device, or an endoscope display), a fish finder, various measurement devices, gauges (e.g., gauges of an automobile, an airplane, or a ship), and a projector.

[Electronic Apparatus]

Embodiments provide an electronic apparatus which may include the light-emitting device.

In embodiments, an electronic apparatus including the light-emitting device may be a flat panel display, a curved display, a computer monitor, a medical monitor, a television, an advertisement board, an indoor light, an outdoor light, a signal light, a head-up display, a fully transparent display, a partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a mobile phone, a tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay, a three-dimensional (3D) display, a virtual reality display, an augmented reality display, a vehicle, a video wall including multiple displays tiled together, a theater screen, a stadium screen, a phototherapy device, or a signboard.

Since the light-emitting device has excellent color conversion efficiency, long lifespan, and the like, an electronic apparatus including the light-emitting device may have characteristics such as high luminance, high resolution, low power consumption, and the like.

[Description of FIGS. 2 and 3]

FIG. 2 is a schematic cross-sectional view of an electronic device according to an embodiment.

The electronic device of FIG. 2 may include a substrate 100, a thin-film transistor (TFT), a light-emitting device, and an encapsulation unit 300.

The substrate 100 may be a flexible substrate, a glass substrate, or a metal substrate. A buffer layer 210 may be arranged on the substrate 100. The buffer layer 210 may prevent penetration of impurities through the substrate 100 and may provide a flat surface on the substrate 100.

A TFT may be arranged on the buffer layer 210. The TFT may include an active layer 220, a gate electrode 240, a source electrode 260, and a drain electrode 270.

The active layer 220 may include an inorganic semiconductor such as silicon or polysilicon, an organic semiconductor, or an oxide semiconductor, and may include a source region, a drain region, and a channel region.

A gate insulating film 230 for insulating the active layer 220 from the gate electrode 240 may be arranged on the active layer 220, and the gate electrode 240 may be arranged on the gate insulating film 230.

An interlayer insulating film 250 may be arranged on the gate electrode 240. The interlayer insulating film 250 may be arranged between the gate electrode 240 and the source electrode 260 to insulate the gate electrode 240 from the source electrode 260 and between the gate electrode 240 and the drain electrode 270 to insulate the gate electrode 240 from the drain electrode 270.

The source electrode 260 and the drain electrode 270 may be arranged on the interlayer insulating film 250. The interlayer insulating film 250 and the gate insulating film 230 may be formed to expose a source region and a drain region of the active layer 220, and the source electrode 260 and the drain electrode 270 may respectively contact the exposed portions of the source region and the drain region of the active layer 220.

The TFT may be electrically connected to a light-emitting device to drive the light-emitting device, and may be covered and protected by a passivation layer 280. The passivation layer 280 may include an inorganic insulating film, an organic insulating film, or any combination thereof. The light-emitting device may be provided on the passivation layer 280. The light-emitting device may include the first electrode 110, the interlayer, and the second electrode 150.

The first electrode 110 may be arranged on the passivation layer 280. The passivation layer 280 may not completely cover the drain electrode 270 and may expose a portion of the drain electrode 270. The first electrode 110 may be connected (e.g., electrically connected) to the exposed portion of the drain electrode 270.

A pixel-defining layer 290 including an insulating material may be arranged on the first electrode 110. The pixel-defining layer 290 may expose a region of the first electrode 110, and an interlayer 130 may be formed on the exposed region of the first electrode 110. The pixel-defining layer 290 may be a polyimide-based organic film or a polyacrylic organic film. Although not illustrated in FIG. 2, at least some layers of the interlayer may extend beyond the upper portion of the pixel defining layer 290 to be provided in the form of a common layer.

The second electrode 150 may be disposed on the interlayer, and a capping layer 170 may be further included on the second electrode 150. The capping layer 170 may be formed to cover the second electrode 150.

The encapsulation unit 300 may be arranged on the capping layer 170. The encapsulation unit 300 may be arranged on a light-emitting device to protect the light-emitting device from moisture and/or oxygen. The encapsulation unit 300 may include: an inorganic film including silicon nitride (SiN_x), silicon oxide (SiO_x), indium tin oxide, indium zinc oxide, or any combination thereof; an organic film including polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate, hexamethyldisiloxane, an acrylic resin (for example, polymethyl methacrylate, polyacrylic acid, or the like), an epoxy-based resin (for example, aliphatic glycidyl ether (AGE), or the like), or any combination thereof; or any combination of the inorganic films and the organic films.

FIG. 3 is a schematic cross-sectional view of an electronic device according to another embodiment.

The electronic device of FIG. 3 may differ from the electronic device of FIG. 2, at least in that a light-shielding pattern 500 and a functional region 400 are further included on the encapsulation unit 300. The functional region 400 may be a color filter area, a color conversion area, or a combination of the color filter area and the color conversion area. In an embodiment, the light-emitting device included in the electronic device of FIG. 3 may be a tandem light-emitting device.

[Description of FIG. 4]

FIG. 4 is a schematic perspective view of an electronic apparatus 1 including a light-emitting device according to an embodiment.

The electronic apparatus 1, which may be an apparatus that displays a moving image or still image, may be not only a portable electronic apparatus, such as a mobile phone, a smartphone, a tablet personal computer (PC), a mobile communication terminal, an electronic notebook, an electronic book, a portable multimedia player (PMP), a navigation device, or an ultra-mobile PC (UMPC), but may also be various products, such as a television, a laptop computer, a monitor, an advertisement board, or an Internet of things (IOT). The electronic apparatus 1 may be any product as described above or a part thereof.

In an embodiment, the electronic apparatus 1 may be a wearable device, such as a smart watch, a watch phone, a glasses-type display, or a head mounted display (HMD), or a part of the wearable device. However, embodiments are not limited thereto.

For example, the electron apparatus 1 may be a dashboard of a vehicle, a center fascia of a vehicle, a center information display (CID) arranged on a dashboard of a vehicle, a room mirror display that replaces a side mirror of a vehicle, an entertainment display for a rear seat of a vehicle or a display arranged on the back of a front seat, a head up display (HUD) installed in the front of a vehicle or projected on a front window glass, or a computer generated hologram augmented reality head up display (CGH AR HUD). FIG. 4 illustrates an embodiment in which the electronic apparatus 1 is a smartphone, for convenience of explanation.

The electronic apparatus 1 may include a display area DA and a non-display area NDA outside the display area DA. The electronic apparatus 1 may implement an image through a two-dimensional array of pixels that are arranged in the display area DA.

The non-display area NDA is an area that does not display an image, and may surround the display area DA. A driver for providing electrical signals or power to display devices arranged in the display area DA may be arranged in the non-display area NDA. A pad, which is an area to which an electronic element, a printed circuit board, or the like may be electrically connected, may be arranged in the non-display area NDA.

In the electronic apparatus 1, a length in the x-axis direction and a length in the y-axis direction may be different from each other. In an embodiment, as illustrated in FIG. 4, the length in the x-axis direction may be shorter than the length in the y-axis direction. In embodiments, the length in the x-axis direction may be the same as the length in the y-axis direction. In other embodiments, the length in the x-axis direction may be longer than the length in the y-axis direction.

[Descriptions of FIGS. 5 and 6A to 6C]

FIG. 5 is a schematic perspective view of an exterior of a vehicle 1000 as an electronic apparatus including a light-emitting device, according to an embodiment. FIGS. 6A to 6C are each a schematic diagram of an interior of a vehicle 1000 according to embodiments.

Referring to FIGS. 5, 6A, 6B, and 6C, the vehicle 1000 may be various apparatuses for moving a subject to be transported, such as a person, an object, or an animal, from a departure point to a destination point. Examples of the vehicle 1000 may include a vehicle traveling on a road or track, a vessel moving over the sea or river, an airplane flying in the sky using the action of air, and the like.

The vehicle 1000 may travel on a road or a track. The vehicle 1000 may move in a selected direction according to the rotation of at least one wheel. Examples of the vehicle 1000 may include a three-wheeled or four-wheeled vehicle, a construction machine, a two-wheeled vehicle, a prime mover device, a bicycle, and a train running on a track.

The vehicle 1000 may include a body having an interior and an exterior, and a chassis that is a portion excluding the body in which mechanical apparatuses necessary for driving are installed. The exterior of the body may include a front panel, a bonnet, a roof panel, a rear panel, a trunk, a pillar provided at a boundary between doors, and the like. The chassis of the vehicle 1000 may include a power generating device, a power transmitting device, a driving device, a steering device, a braking device, a suspension device, a transmission device, a fuel device, front/rear wheels, left/right wheels, and the like.

The vehicle 1000 may include a side window glass 1100, a front window glass 1200, a side mirror 1300, a cluster 1400, a center fascia 1500, a passenger seat dashboard 1600, and a display device 2.

The side window glass 1100 and the front window glass 1200 may be partitioned by a pillar arranged between the side window glass 1100 and the front window glass 1200.

The side window glass 1100 may be installed on a side of the vehicle 1000. In an embodiment, the side window glass 1100 may be installed on a door of the vehicle 1000. Multiple side window glasses 1100 may be provided and may face each other. In an embodiment, the side window glass 1100 may include a first side window glass 1110 and a second side window glass 1120. In an embodiment, the first side window glass 1110 may be arranged adjacent to the cluster 1400, and the second side window glass 1120 may be arranged adjacent to the passenger seat dashboard 1600.

In an embodiment, the side window glasses 1100 may be spaced apart from each other in the x-direction or the −x-direction. For example, the first side window glass 1110 and the second side window glass 1120 may be spaced apart from each other in the x-direction or the −x-direction. For example, an imaginary straight line L connecting the side window glasses 1100 may extend in the x-direction or the −x-direction. For example, an imaginary straight line L connecting the first side window glass 1110 and the second side window glass 1120 to each other may extend in the x-direction or the −x-direction.

The front window glass 1200 may be installed at the front of the vehicle 1000. The front window glass 1200 may be arranged between the side window glasses 1100 facing each other.

The side mirror 1300 may provide a rear view of the vehicle 1000. The side mirror 1300 may be installed on the exterior of the body. In an embodiment, multiple side mirrors 1300 may be provided. One of the side mirrors 1300 may be arranged outside the first side window glass 1110. Another one of the side mirrors 1300 may be arranged outside the second side window glass 1120.

The cluster 1400 may be arranged in the front of a steering wheel. The cluster 1400 may include a tachometer, a speedometer, a coolant thermometer, a fuel gauge, a turn signal indicator, a high beam indicator, a warning light, a seat belt warning light, an odometer, an automatic transmission selector indicator light, a door open warning light, an engine oil warning light, and/or a low fuel warning light.

The center fascia 1500 may include a control panel on which buttons for adjusting an audio device, an air conditioning device, and a seat heater are disposed. The center fascia 1500 may be arranged on a side of the cluster 1400.

The passenger seat dashboard 1600 may be spaced apart from the cluster 1400 with the center fascia 1500 arranged therebetween. In an embodiment, the cluster 1400 may be arranged to correspond to a driver seat (not shown), and the passenger seat dashboard 1600 may be disposed to correspond to a passenger seat (not shown). In an embodiment, the cluster 1400 may be adjacent to the first side window glass 1110, and the passenger seat dashboard 1600 may be adjacent to the second side window glass 1120.

In an embodiment, the display device 2 may include a display panel 3, and the display panel 3 may display an image. The display device 2 may be arranged inside the vehicle 1000. In an embodiment, the display device 2 may be arranged between the side window glasses 1100 facing each other. The display device 2 may be arranged on at least one of the cluster 1400, the center fascia 1500, and the passenger seat dashboard 1600.

The display device 2 may include an organic light-emitting display device, an inorganic electroluminescent (EL) display device, a quantum dot display device, or the like. Hereinafter, an organic light-emitting display device including the light-emitting device according to an embodiment will be described as an example of the display device 2. However, various types of display devices as described herein may be used in embodiments.

Referring to FIG. 6A, the display device 2 may be arranged on the center fascia 1500. In an embodiment, the display device 2 may display navigation information. In an embodiment, the display device 2 may display information regarding audio settings, video settings, or vehicle settings.

Referring to FIG. 6B, the display device 2 may be arranged on the cluster 1400. The cluster 1400 may display driving information and the like through the display device 2. For example, the cluster 1400 may digitally implement driving information. The cluster 1400 may digitally display vehicle information and driving information as images. For example, a needle and a gauge of a tachometer and various warning lights or icons may be displayed by a digital signal.

Referring to FIG. 6C, the display device 2 may be arranged on the passenger seat dashboard 1600. The display device 2 may be embedded in the passenger seat dashboard 1600 or arranged on the passenger seat dashboard 1600. In an embodiment, the display device 2 arranged on the passenger seat dashboard 1600 may display an image related to information displayed on the cluster 1400 and/or information displayed on the center fascia 1500. In embodiments, the display device 2 arranged on the passenger seat dashboard 1600 may display information that is different from the information displayed on the cluster 1400 and/or the information displayed on the center fascia 1500.

[Manufacturing Method]

Respective layers included in the hole transport region 120, the emission layer 130, and respective layers included in the electron transport region 140 may be formed in a selected region by using various methods, such as vacuum deposition, spin coating, casting, a Langmuir-Blodgett (LB) method, ink-jet printing, laser-printing, laser-induced thermal imaging, and the like.

When respective layers included in the hole transport region 120, the emission layer 130, and respective layers included in the electron transport region 140 are formed by vacuum deposition, the deposition may be performed at a deposition temperature of about 100° C. to about 500° C., a vacuum degree of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition rate of about 0.01 Å/sec to about 100 Å/sec, depending on a material to be included in a layer to be formed and the structure of a layer to be formed.

[Definitions of Terms]

The term “C₃-C₆₀ carbocyclic group” as used herein may be a cyclic group consisting of carbon atoms as the only ring-forming atoms and having 3 to 60 carbon atoms. The term “C₁-C₆₀ heterocyclic group” as used herein may be a cyclic group that has 1 to 60 carbon atoms and further has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom. The C₃-C₆₀ carbocyclic group and the C₁-C₆₀ heterocyclic group may each be a monocyclic group consisting of one ring or a polycyclic group in which two or more rings are condensed with each other. For example, the number of ring-forming atoms in a C₁-C₆₀ heterocyclic group may be from 3 to 61.

The term “cyclic group” as used herein may be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group.

The term “π electron-rich C₃-C₆₀ cyclic group” as used herein may be a cyclic group that has 3 to 60 carbon atoms and may not include *—N═*′ as a ring-forming moiety.

The term “π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group” as used herein may be a heterocyclic group that has 1 to 60 carbon atoms and may include *—N═*′ as a ring-forming moiety.

In embodiments,

• • a C₃-C₆₀ carbocyclic group may be a T1 group or a group in which two or more T1 groups are condensed with each other (for example, a cyclopentadiene group, an adamantane group, a norbornane group, a benzene group, a pentalene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a perylene group, a pentaphene group, a heptalene group, a naphthacene group, a picene group, a hexacene group, a pentacene group, a rubicene group, a coronene group, an ovalene group, an indene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, an indenophenanthrene group, or an indenoanthracene group),
  • a C₁-C₆₀ heterocyclic group may be a T2 group, a group in which at least two T2 groups are condensed with each other, or a group in which at least one T2 group and at least one T1 group are condensed with each other (for example, a pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothienodibenzothiophene group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, an azadibenzofuran group, or the like),
  • a π electron-rich C₃-C₆₀ cyclic group may be a T1 group, a group in which at least two T1 groups are condensed with each other, a T3 group, a group in which at least two T3 groups are condensed with each other, or a group in which at least one T3 group and at least one T1 group are condensed with each other (for example, a C₃-C₆₀ carbocyclic group, a 1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothienodibenzothiophene group, or the like), and
  • a π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group may be a T4 group, a group in which at least two T4 groups are condensed with each other, a group in which at least one T4 group and at least one T1 group are condensed with each other, a group in which at least one T4 group and at least one T3 group are condensed with each other, or a group in which at least one T4 group, at least one T1 group, and at least one T3 group are condensed with one another (for example, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, an azadibenzofuran group, and the like).

The T1 group may be a cyclopropane group, a cyclobutane group, a cyclopentane group, a cyclohexane group, a cycloheptane group, a cyclooctane group, a cyclobutene group, a cyclopentene group, a cyclopentadiene group, a cyclohexene group, a cyclohexadiene group, a cycloheptene group, an adamantane group, a norbornane (or bicyclo[2.2.1]heptane) group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.2]octane group, or a benzene group.

The T2 group may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a tetrazine group, a pyrrolidine group, an imidazolidine group, a dihydropyrrole group, a piperidine group, a tetrahydropyridine group, a dihydropyridine group, a hexahydropyrimidine group, a tetrahydropyrimidine group, a dihydropyrimidine group, a piperazine group, a tetrahydropyrazine group, a dihydropyrazine group, a tetrahydropyridazine group, or a dihydropyridazine group.

The T3 group may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, or a borole group.

The T4 group may be a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or a tetrazine group.

The terms “cyclic group,” “C₃-C₆₀ carbocyclic group,” “C₁-C₆₀ heterocyclic group,” “π electron-rich C₃-C₆₀ cyclic group,” and “π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group” as used herein may each be a group condensed to any cyclic group, a monovalent group, or a polyvalent group (for example, a divalent group, a trivalent group, a tetravalent group, etc.), according to the structure of a formula for which the corresponding term is used.

For example, a “benzene group” may be a benzo group, a phenyl group, a phenylene group, or the like, which may be readily understood by one of ordinary skill in the art according to the structure of a formula including the “benzene group.”

Examples of a monovalent C₃-C₆₀ carbocyclic group or a monovalent C₁-C₆₀ heterocyclic group may include a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

Examples of a divalent C₃-C₆₀ carbocyclic group or a divalent C₁-C₆₀ heterocyclic group may include a C₃-C₁₀ cycloalkylene group, a C₁-C₁₀ heterocycloalkylene group, a C₃-C₁₀ cycloalkenylene group, a C₁-C₁₀ heterocycloalkenylene group, a C₆-C₆₀ arylene group, a C₁-C₆₀ heteroarylene group, a divalent non-aromatic condensed polycyclic group, and a divalent non-aromatic condensed heteropolycyclic group.

The term “C₁-C₆₀ alkyl group” as used herein may be a linear or branched monovalent aliphatic hydrocarbon group that has one to sixty carbon atoms, and examples thereof may include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, and a tert-decyl group.

The term “C₁-C₆₀ alkylene group” as used herein may be a divalent group having a same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein may be a monovalent hydrocarbon group having at least one carbon-carbon double bond in the middle or at a terminus of a C₂-C₆₀ alkyl group, and examples thereof may include an ethenyl group, a propenyl group, a butenyl group, and the like.

The term “C₂-C₆₀ alkenylene group” as used herein may be a divalent group having a same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein may be a monovalent hydrocarbon group having at least one carbon-carbon triple bond in the middle or at a terminus of a C₂-C₆₀ alkyl group, and examples thereof may include an ethynyl group, a propynyl group, and the like.

The term “C₂-C₆₀ alkynylene group” as used herein may be a divalent group having a same structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein may be a monovalent group represented by —O(A₁₀₁) (wherein A₁₀₁ may be a C₁-C₆₀ alkyl group), and examples thereof may include a methoxy group, an ethoxy group, an isopropyloxy group, and the like.

The term “C₃-C₁₀ cycloalkyl group” as used herein may be a monovalent saturated hydrocarbon cyclic group having 3 to 10 carbon atoms, and examples thereof may include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group (or bicyclo[2.2.1]heptyl group), a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.2]octyl group, and the like.

The term “C₃-C₁₀ cycloalkylene group” as used herein may be a divalent group having a same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein may be a monovalent cyclic group having 1 to 10 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms, and examples thereof may include a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, a tetrahydrothiophenyl group, and the like.

The term “C₁-C₁₀ heterocycloalkylene group” as used herein may be a divalent group having a same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein may be a monovalent cyclic group that has three to ten carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and examples thereof may include a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, and the like.

The term “C₃-C₁₀ cycloalkenylene group” as used herein may be a divalent group having a same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein may be a monovalent cyclic group having 1 to 10 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms, and having at least one carbon-carbon double bond in the cyclic structure thereof. Examples of a C₁-C₁₀ heterocycloalkenyl group may include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, a 2,3-dihydrothiophenyl group, and the like.

The term “C₁-C₁₀ heterocycloalkenylene group” as used herein may be a divalent group having a same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein may be a monovalent group having a carbocyclic aromatic system of 6 to 60 carbon atoms.

The term “C₆-C₆₀ arylene group” as used herein may be a divalent group having a carbocyclic aromatic system of 6 to 60 carbon atoms.

Examples of a C₆-C₆₀ aryl group may include a phenyl group, a pentalenyl group, a naphthyl group, an azulenyl group, an indacenyl group, an acenaphthyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a heptalenyl group, a naphthacenyl group, a picenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, and the like.

When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the respective rings may be condensed with each other.

The term “C₁-C₆₀ heteroaryl group” as used herein may be a monovalent group having a heterocyclic aromatic system of 1 to 60 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms.

The term “C₁-C₆₀ heteroarylene group” as used herein may be a divalent group having a heterocyclic aromatic system of 1 to 60 carbon atoms, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms.

Examples of a C₁-C₆₀ heteroaryl group may include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, a benzoquinolinyl group, an isoquinolinyl group, a benzoisoquinolinyl group, a quinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl group, a phenanthrolinyl group, a phthalazinyl group, and a naphthyridinyl group.

When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the respective rings may be condensed with each other.

The term “monovalent non-aromatic condensed polycyclic group” as used herein may be a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed to each other, only carbon atoms as ring-forming atoms, and no aromaticity in its molecular structure as a whole. Examples of a monovalent non-aromatic condensed polycyclic group may include an indenyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, an indenophenanthrenyl group, an indeno anthracenyl group, and the like.

The term “divalent non-aromatic condensed polycyclic group” as used herein may be a divalent group having a same structure as the monovalent non-aromatic condensed polycyclic group described above.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein may be a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings condensed to each other, further including, in addition to carbon atoms, at least one heteroatom, as ring-forming atoms, and having no aromaticity in its molecular structure as a whole. Examples of a monovalent non-aromatic condensed heteropolycyclic group may include a pyrrolyl group, a thiophenyl group, a furanyl group, an indolyl group, a benzoindolyl group, a naphtho indolyl group, an isoindolyl group, a benzoisoindolyl group, a naphthoisoindolyl group, a benzosilolyl group, a benzothiophenyl group, a benzofuranyl group, a carbazolyl group, a dibenzosilolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, an azacarbazolyl group, an azafluorenyl group, an azadibenzosilolyl group, an azadibenzothiophenyl group, an azadibenzofuranyl group, a pyrazolyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzopyrazolyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a benzoxadiazolyl group, a benzothiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an imidazotriazinyl group, an imidazopyrazinyl group, an imidazopyridazinyl group, an indenocarbazolyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a benzosilolocarbazolyl group, a benzoindolocarbazolyl group, a benzocarbazolyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, a benzonaphthosilolyl group, a benzofurodibenzofuranyl group, a benzofurodibenzothiophenyl group, and a benzothienodibenzothiophenyl group.

The term “divalent non-aromatic condensed heteropolycyclic group” as used herein may be a divalent group having a same structure as the monovalent non-aromatic condensed heteropolycyclic group described above.

The term “C₆-C₆₀ aryloxy group” as used herein may be a group represented by —O(A₁₀₂) (wherein A₁₀₂ may be a C₆-C₆₀ aryl group).

The term “C₆-C₆₀ arylthio group” as used herein may be a group represented by —S(A₁03) (wherein A₁₀₃ may be a C₆-C₆₀ aryl group).

The term “C₇-C₆₀ arylalkyl group” as used herein may be a group represented by -(A₁₀₄)(A₁₀₅) (wherein A₁₀₄ may be a C₁-C₅₄ alkylene group, and A₁₀₅ may be a C₆-C₅₉ aryl group).

The term “C₂-C₆₀ heteroarylalkyl group” as used herein may be a group represented by -(A₁₀₆)(A₁₀₇) (wherein A₁₀₆ may be a C₁-C₅₉ alkylene group, and A₁₀₇ may be a C₁-C₅₉ heteroaryl group).

In the specification, the group “R_10a” and “R_10b” may each independently be:

• • deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;
  • a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₂-C₆₀ heteroarylalkyl group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or any combination thereof;
  • a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, or a C₂-C₆₀ heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₂-C₆₀ heteroarylalkyl group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof; or
  • —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂).

In the specification, the groups Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently be:

• • hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group;
  • a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₇-C₆₀ arylalkyl group, or a C₂-C₆₀ heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.

The term “heteroatom” as used herein may be any atom other than a carbon atom or a hydrogen atom. Examples of a heteroatom may include O, S, N, P, Si, B, Ge, Se, and any combination thereof.

In the specification, a third-row transition metal may be hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), or the like.

In the specification, “D” refers to hydrogen, “Ph” refers to a phenyl group, “Me” refers to a methyl group, “Et” refers to an ethyl group, “^tBu” or “Bu^t” each refers to a tert-butyl group, “OMe” refers to a methoxy group, and “pin” refers to pinacolato.

The term “biphenyl group” as used herein may be a “phenyl group substituted with a phenyl group.” For example, the “biphenyl group” may be a substituted phenyl group having a C₆-C₆₀ aryl group as a substituent.

The term “terphenyl group” as used herein may be a “phenyl group substituted with a biphenyl group.” For example, the “terphenyl group” may be a substituted phenyl group having, as a substituent, a C₆-C₆₀ aryl group substituted with a C₆-C₆₀ aryl group.

The symbols *, *′, and *″ as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula or moiety.

In the specification, the terms “x-axis,” “y-axis,” and “z-axis” are not limited to three axes in an orthogonal coordinate system (e.g., a Cartesian coordinate system), and may be interpreted in a broader sense than the aforementioned three axes in an orthogonal coordinate system. For example, the x-axis, y-axis, and z-axis may be axes that are orthogonal to each other, or may be axes that are in different directions that are not orthogonal to each other.

Hereinafter, compounds according to embodiments and light-emitting devices according to embodiments will be described in further detail with reference to the Synthesis Examples and Examples. The wording “B was used instead of A” used in describing the Synthesis Examples means that an identical molar equivalent of B was used in place of A.

Synthesis Example 1 (Synthesis of Compound BD1)

Synthesis of Intermediate BD1-1

Synthesis of Intermediate BD1-2

Synthesis of Compound BD1

Synthesis Example 2 (Synthesis of Compound BD2)

Synthesis of Intermediate BD2-1

Synthesis of Intermediate BD2-2

Synthesis of Compound BD2

Synthesis Example 3 (Synthesis of Compound BD3)

Synthesis of Intermediate BD3-1

Synthesis of Intermediate BD3-2

Synthesis of Compound BD3

Synthesis Example 4 (Synthesis of Compound BD6)

Synthesis of Intermediate BD6-1

Synthesis of Intermediate BD6-2

Synthesis of Compound BD6

Synthesis Example 5 (Synthesis of Compound BD8)

Synthesis of Intermediate BD8-1

Synthesis of Intermediate BD8-2

Synthesis of Compound BD8

Synthesis Example 6 (Synthesis of Compound BD11)

Synthesis of Intermediate BD11-1

Synthesis of Intermediate BD11-2

Synthesis of Compound BD11

Synthesis Example 7 (Synthesis of Compound BD16)

Synthesis of Intermediate BD16-1

Synthesis of Intermediate BD16-2

Synthesis of Compound BD16

Synthesis Example 8 (Synthesis of Compound BD24)

Synthesis of Intermediate BD24-1

Synthesis of Intermediate BD24-2

Synthesis of Compound BD24

A method of synthesizing the compounds represented by Formula 1 may be readily recognized with reference to Synthesis Examples 1 to 8.

¹H NMR and MS/FAB of the compounds synthesized according to Synthesis Examples 1 to 8 are shown in Table 1 below.

	TABLE 1
	MS/FAB
Compound	1H NMR (CDCl3, 400 MHz)	found	calc.
BD1	8.56(m, 2H), 8.39(d, 1H), 8.19(d, 1H), 7.87(d, 2H), 7.73(m,	992.47	993.22
	1H), 7.58(d, 1H), 7.50-7.19(m, 17H), 7.00(m, 1H), 6.69(d,
	1H), 1.32(d, 9H)
BD2	8.39(d, 1H), 8.19-8.20(m, 3H), 7.68(d, 2H), 7.50-7.41(m, 8H),	1016.47	1017.42
	7.20-7.08(m, 5H), 6.95-6.90(m, 3H), 6.69-6.66(m, 2H),
	2.36(m, 6H), 1.32(d, 9H)
BD3	8.26-8.19(m, 4H), 7.58(m, 1H), 7.50-7.39(m, 10H), 7.20-	1007.48	1008.23
	7.08(m, 6H), 6.95(m, 2H), 6.50(d, 1H), 5.65(d, 1H), 2.51(d,
	3H), 1.32(d, 9H)
BD6	8.39(d, 1H), 8.20-8.19(m, 3H), 7.76(d, 1H), 7.58(d, 1H), 7.50-	1025.36	1026.15
	7.41(m, 13H), 7.24-7.08(m, 7H), 6.90(d, 1H), 6.69-6.66(m,
	2H), 1.32(d, 9H)
BD8	8.26-8.19(m, 4H), 7.88(m, 1H), 7.58(m, 1H), 7.50-7.39(m,	1016.54	1017.30
	10H), 7.20-7.08(m, 6H), 6.95(m, 2H), 6.80(d, 1H), 6.50(d,
	1H), 1.32(d, 9H)
BD11	8.26-8.19(m, 4H), 7.58(m, 1H), 7.50-7.41(m, 10H), 7.20-	1072.60	1073.41
	7.08(m, 6H), 6.95(m, 2H), 6.50(d, 1H), 5.67(d, 1H), 1.36-
	1.32(d, 18H)
BD16	8.26-8.19(m, 4H), 7.68(d, 2H), 7.58(m, 1H), 7.50-7.39(m,	1057.58	1058.37
	8H), 7.20-7.08(m, 4H), 6.95(m, 2H), 6.50(m, 1H), 5.65(d, 1H),
	2.51(d, 3H), 2.36(d, 6H), 1.32(d, 9H)
BD24	8.33-8.19(m, 7H), 8.02(m, 1H), 7.58-7.31(m, 13H), 7.20-	1036.51	1037.29
	7.08(m, 6H), 6.95(m, 2H), 6.50(m, 1H), 6.32(d, 1H)

Evaluation Example 1

The HOMO and LUMO values of the compounds of the Synthesis Examples and Compounds A, B, and C were measured using a method described in Table 2, and the results thereof are shown in Table 3.

The triplet energy levels (Ti), dipoles, and metal to ligand charge transfer (MLCT) of the compounds of synthesis examples and Compounds A, B, and C were measured using quantum chemistry calculation software after the singlet (Si) state was optimized, and the results thereof are shown in Table 3.

TABLE 2
HOMO energy      A potential (V)-current (A) graph of each compound was obtained by using
level evaluation cyclic voltammetry (CV) (electrolyte: 0.1M Bu4NPF6/solvent: dimethyl
method           formamide (DMF)/electrode: 3 electrode system (working electrode: GC,
                 reference electrode: Ag/AgCl, auxiliary electrode: Pt)), and from oxidation
                 onset of the graph, the HOMO energy level of each compound was
                 calculated.
LUMO energy      A potential (V)-current (A) graph of each compound was obtained by using
level evaluation cyclic voltammetry (CV) (electrolyte: 0.1M Bu4NPF6/solvent: dimethyl
method           formamide (DMF)/electrode: 3 electrode system (working electrode: GC,
                 reference electrode: Ag/AgCl, auxiliary electrode: Pt)), and from reduction
                 onset of the graph, the LUMO energy level of each compound was
                 calculated.

TABLE 3
Organometallic	HOMO	LUMO	T1	T1	Dipole	MLCT
compound	(eV)	(eV)	(eV)	(nm)	(Debye)	(%)
A	−4.88	−1.50	2.66	466.57	8.05	12.90
B	−4.86	−1.02	2.83	437.66	8.24	19.33
C	−5.04	−1.79	2.39	518.10	8.42	20.35
BD1	−4.88	−1.48	2.69	460.84	7.51	11.44
BD2	−4.88	−1.46	2.70	458.94	7.51	12.00
BD3	−5.04	−1.51	2.76	449.32	7.28	17.03
BD6	−5.05	−1.51	2.76	448.83	7.57	14.58
BD8	−5.08	−1.53	2.76	448.48	7.57	16.28
BD11	−5.04	−1.52	2.76	449.47	7.56	16.73
BD16	−5.03	−1.49	2.76	448.53	7.04	16.81
BD24	−5.09	−1.55	2.69	461.12	7.99	16.89

From Table 3, it can be confirmed that Compounds A and C have a relatively long wavelength of T1, whereas the compounds of the Synthesis Examples have a relatively short wavelength of T1.

Example 1

As an anode, a glass substrate with a 15 Ω/cm² (1,200 Å) ITO formed thereon was cut to a size of 50 mm×50 mm×0.7 mm, sonicated in isopropyl alcohol and pure water for 5 minutes each, cleaned by irradiation of ultraviolet rays and exposure to ozone for 30 minutes, and mounted on a vacuum deposition apparatus.

2-TNATA was vacuum-deposited on the anode to form a hole injection layer having a thickness of 600 Å. NPB was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 300 Å.

10% of Compound BD1 as a dopant and a mixed host of ETH2 and HTH2 in a weight ratio of 5:5 were co-deposited on the hole transport layer to form an emission layer having a thickness of 300 Å. ETH2 was vacuum-deposited thereon to form a hole blocking layer having a thickness of 50 Å. Alq₃ was deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å. LiF, which is an alkali metal halide, was deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å. Al was vacuum-deposited on the electron injection layer to form an LiF/Al electrode (negative electrode) having a thickness of 3,000 Å, thereby completing the manufacture of a light-emitting device.

Examples 2 to 8 and Comparative Examples 1 to 3

Light-emitting devices were manufactured in the same manner as in Example 1, except that, in forming an emission layer, compounds shown in Table 4 were used instead of Compound BD1.

Evaluation Example 2

The driving voltage at 1,000 cd/n², luminescence efficiency (cd/A), maximum emission wavelength (nm), and lifespan (T₉₀, hr) of each of the light-emitting devices of Examples 1 to 8 and Comparative Examples 1 to 3 were measured using Keithley MU 236 and luminance meter PR650, and the results thereof are shown in Table 4. The lifespan (T₉₀) indicates the time (hr) taken to reach a luminance of 90% with respect to initial luminance.

TABLE 4
					Maximum	Lifespan
			Driving	Luminescence	emission	(T90, hr)
	Organometallic	Luminance	voltage	efficiency	wavelength	(at 1000
No.	compound	(cd/m2)	(V)	(cd/A)	(nm)	cd/m2)
Example 1	BD1	1000	4.5	24.3	460	100
Example 2	BD2	1000	4.4	23.9	462	98
Example 3	BD3	1000	4.4	23.2	461	101
Example 4	BD6	1000	4.5	24.1	459	94
Example 5	BD8	1000	4.5	23.5	461	97
Example 6	BD11	1000	4.4	22.4	462	104
Example 7	BD16	1000	4.5	21.5	461	106
Example 8	BD24	1000	4.6	22.7	461	89
Comparative	A	1000	4.7	16.8	462	65
Example 1
Comparative	B	1000	4.9	20.1	453	30
Example 2
Comparative	C	1000	4.8	19.4	465	50
Example 3

From Table 4, it can be confirmed that the light-emitting devices of Examples 1 to 8 have improved driving voltage, improved luminescence efficiency, and long lifespan, compared to the light-emitting devices of Comparative Examples 1 to 3, and emit deep blue light.

As is apparent from the foregoing description, the organometallic compound has excellent electrical characteristics, excellent stability, and the like, and thus, a light-emitting device employing the organometallic compound may have improved color purity, improved luminescence efficiency, and improved lifespan.

Embodiments have been disclosed herein, and although terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for the purposes of limitation. In some instances, as would be apparent by one of ordinary skill in the art, features, characteristics, and/or elements described in connection with an embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the disclosure as set forth in the claims.

Claims

1. A light-emitting device comprising:

a first electrode;

a second electrode facing the first electrode;

an interlayer between the first electrode and the second electrode and comprising an emission layer; and

an organometallic compound represented by Formula 1:

wherein in Formula 1,

M is platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), or osmium (Os),

X1 to X4 are each independently a carbon atom (C) or a nitrogen atom (N),

rings CY1 to CY4 are each independently a C5-C60 carbocyclic group or a C1-C60 heterocyclic group,

L1 to L3 are each independently a single bond, *—O—*′, *—S—*′, *—C(R5)(R6)—*′, *—C(R5)═*′, *═C(R5)—*′, *—C(R5)═C(R6)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R5)—*′, *—N(R5)—*′, *—P(R5)—*′, *—Si(R5)(R6)—*′, *—P(R5)(R6)—*′, or *—Ge(R5)(R6)—*′, L4 is a C5-C60 carbocyclic group unsubstituted or substituted with R10b or a C1-C60 heterocyclic group unsubstituted or substituted with R10b,

a1 to a3 are each independently an integer from 0 to 3,

when a1 is 0, rings CY1 and CY2 are not linked to each other via (L1)a1,

when a1 is 2 or 3, two or three of L1 are identical to or different from each other,

when a2 is 0, rings CY2 and CY3 are not linked to each other via (L2)a2,

when a2 is 2 or 3, two or three of L2 are identical to or different from each other,

when a3 is 0, rings CY3 and CY4 are not linked to each other via (L3)a3,

when a3 is 2 or 3, two or three of L3 are identical to or different from each other,

a4 is an integer from 1 to 3,

when a4 is 2 or 3, two or three of L4 are identical to or different from each other,

a ring formed by M, X1-containing CY1, (L4)a4, and X4-containing CY4 is a 9-membered ring,

R1 to R6 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group unsubstituted or substituted with at least one R10a, a C2-C60 alkenyl group unsubstituted or substituted with at least one R10a, a C2-C60 alkynyl group unsubstituted or substituted with at least one R10a, a C1-C60 alkoxy group unsubstituted or substituted with at least one R10a, a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a, a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a, a C6-C60 aryloxy group unsubstituted or substituted with at least one R10a, a C6-C60 arylthio group unsubstituted or substituted with at least one R10a, a C7-C60 arylalkyl group unsubstituted or substituted with at least one R10a, a C2-C60 heteroarylalkyl group unsubstituted or substituted with at least one R10a, —C(Q1)(Q2)(Q3), —Si(Q1)(Q2)(Q3), —N(Q1)(Q2), —B(Q1)(Q2), —C(═O)(Q1), —S(═O)2(Q1), or —P(═O)(Q1)(Q2),

b1 to b4 are each independently an integer from 0 to 10,

R10b and R1 are optionally linked to each other to form a C3-C20 carbocyclic group or a C1-C20 heterocyclic group,

R10b and R4 are optionally linked to each other to form a C3-C20 carbocyclic group or a C1-C20 heterocyclic group,

R10a and R10b are each independently:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;

a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, or a C1-C60 alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, a C2-C60 heteroarylalkyl group, —Si(Q11)(Q12)(Q13), —N(Q11)(Q12), —B(Q11)(Q12), —C(═O)(Q11), —S(═O)2(Q11), —P(═O)(Q11)(Q12), or a combination thereof;

a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, or a C2-C60 heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group, a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, a C2-C60 heteroarylalkyl group, —Si(Q21)(Q22)(Q23), —N(Q21)(Q22), —B(Q21)(Q22), —C(═O)(Q21), —S(═O)2(Q21), —P(═O)(Q21)(Q22), or a combination thereof; or

—Si(Q31)(Q32)(Q33), —N(Q31)(Q32), —B(Q31)(Q32), —C(═O)(Q31), —S(═O)2(Q31), or —P(═O)(Q31)(Q32), and

Q1 to Q3, Q11 to Q13, Q21 to Q23, and Q31 to Q33 are each independently:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group; or

a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C7-C60 arylalkyl group, or a C2-C60 heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C1-C60 alkyl group, a C1-C60 alkoxy group, a phenyl group, a biphenyl group, or a combination thereof.

2. The light-emitting device of claim 1, wherein the interlayer comprises the organometallic compound.

3. The light-emitting device of claim 1, further comprising:

a second compound comprising at least one 71 electron-deficient nitrogen-containing C1-C60 heterocyclic group, a third compound comprising a group represented by Formula 3, a fourth compound that is a delayed fluorescence compound, or a combination thereof, wherein

the organometallic compound, the second compound, the third compound, and the fourth compound are different from each other:

wherein in Formula 3,

rings CY71 and CY72 are each independently a π electron-rich C3-C60 cyclic group or a pyridine group,

X71 is: a single bond; or a linking group including O, S, N, B, C, Si, or a combination thereof, and

* indicates a binding site to an atom included in the remaining portion other than the group represented by Formula 3 in the third compound.

4. The light-emitting device of claim 3, wherein

the interlayer further comprises: a hole transport region between the first electrode and the emission layer; and an electron transport region between the emission layer and the second electrode,

the hole transport region comprises a hole injection layer, a hole transport layer, an emission auxiliary layer, an electron blocking layer, or a combination thereof,

the electron transport region comprises a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or a combination thereof,

the emission layer comprises: the organometallic compound; and the second compound, the third compound, the fourth compound, or a combination thereof, and

the emission layer emits blue light.

5. An electronic device comprising the light-emitting device of claim 1.

6. The electronic device of claim 5, further comprising:

a thin-film transistor electrically connected to the light-emitting device; and

a color filter, a color conversion layer, a touch screen layer, a polarizing layer, or a combination thereof.

7. An electronic apparatus comprising the light-emitting device of claim 1, wherein the electronic apparatus is a flat panel display, a curved display, a computer monitor, a medical monitor, a television, an advertisement board, an indoor light, an outdoor light, a signal light, a head-up display, a fully transparent display, a partially transparent display, a flexible display, a rollable display, a foldable display, a stretchable display, a laser printer, a telephone, a mobile phone, a tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay, a three-dimensional (3D) display, a virtual reality display, an augmented reality display, a vehicle, a video wall including multiple displays tiled together, a theater screen, a stadium screen, a phototherapy device, or a signboard.

8. An organometallic compound represented by Formula 1:

wherein in Formula 1,

M is platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), or osmium (Os),

X1 to X4 are each independently a carbon atom (C) or a nitrogen atom (N),

rings CY1 to CY4 are each independently a C5-C60 carbocyclic group or a C1-C60 heterocyclic group,

L1 to L3 may each independently be *—O—*′, *—S—*′, *—C(R5)(R6)—*′, *—C(R5)═*′, *═C(R5)—*′,*—C(R5)═C(R6)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R5)—*′, *—N(R5)—*′, *—P(R5)—*′, *—Si(R5)(R6)—*′, *—P(R5)(R6)—*′, or *—Ge(R5)(R6)—*′,

L4 is a C5-C60 carbocyclic group unsubstituted or substituted with R10b or a C1-C60 heterocyclic group unsubstituted or substituted with R10b,

a1 to a3 are each independently an integer from 0 to 3,

when a1 is 0, rings CY1 and CY2 are not linked to each other via (L1)a1,

when a1 is 2 or 3, two or three of L1 are identical to or different from each other,

when a2 is 0, rings CY2 and CY3 are not linked to each other via (L2)a2,

when a2 is 2 or 3, two or three of L2 are identical to or different from each other,

when a3 is 0, rings CY3 and CY4 are not linked to each other via (L3)a3,

when a3 is 2 or 3, two or three of L3 are identical to or different from each other,

a4 is an integer from 1 to 3,

when a4 is 2 or 3, two or more of L4 are identical to or different from each other,

a ring formed by M, X1-containing CY1, (L4)a4, and X4-containing CY4 is a 9-membered ring,

R1 to R6 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group unsubstituted or substituted with at least one R10a, a C2-C60 alkenyl group unsubstituted or substituted with at least one R10a, a C2-C60 alkynyl group unsubstituted or substituted with at least one R10a, a C1-C60 alkoxy group unsubstituted or substituted with at least one R10a, a C3-C60 carbocyclic group unsubstituted or substituted with at least one R10a, a C1-C60 heterocyclic group unsubstituted or substituted with at least one R10a, a C6-C60 aryloxy group unsubstituted or substituted with at least one R10a, a C6-C60 arylthio group unsubstituted or substituted with at least one R10a, a C7-C60 arylalkyl group unsubstituted or substituted with at least one R10a, a C2-C60 heteroarylalkyl group unsubstituted or substituted with at least one R10a, —C(Q1)(Q2)(Q3), —Si(Q1)(Q2)(Q3), —N(Q1)(Q2), —B(Q1)(Q2), —C(═O)(Q1), —S(═O)2(Q1), or —P(═O)(Q1)(Q2),

b1 to b4 are each independently an integer from 0 to 10,

R10b and R1 are optionally linked to each other to form a C3-C20 carbocyclic group or a C1-C20 heterocyclic group,

R10b and R4 are optionally linked to each other to form a C3-C20 carbocyclic group or a C1-C20 heterocyclic group,

R10a and R10b are each independently:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;

a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, or a C1-C60 alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, a C2-C60 heteroarylalkyl group, —Si(Q11)(Q12)(Q13), —N(Q11)(Q12), —B(Q11)(Q12), —C(═O)(Q11), —S(═O)2(Q11), —P(═O)(Q11)(Q12), or a combination thereof;

a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, or a C2-C60 heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group, a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C6-C60 aryloxy group, a C6-C60 arylthio group, a C7-C60 arylalkyl group, a C2-C60 heteroarylalkyl group, —Si(Q21)(Q22)(Q23), —N(Q21)(Q22), —B(Q21)(Q22), —C(═O)(Q21), —S(═O)2(Q21), —P(═O)(Q21)(Q22), or a combination thereof; or

—Si(Q31)(Q32)(Q33), —N(Q31)(Q32), —B(Q31)(Q32), —C(═O)(Q31), —S(═O)2(Q31), or —P(═O)(Q31)(Q32), and

Q1 to Q3, Q11 to Q13, Q21 to Q23, and Q31 to Q33 are each independently:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group; or

a C3-C60 carbocyclic group, a C1-C60 heterocyclic group, a C7-C60 arylalkyl group, or a C2-C60 heteroarylalkyl group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C1-C60 alkyl group, a C1-C60 alkoxy group, a phenyl group, a biphenyl group, or a combination thereof.

9. The organometallic compound of claim 8, wherein the organometallic compound is represented by Formula 1-1 or Formula 1-2:

wherein in Formulae 1-1 and 1-2,

X11 and X41 are each independently C or N, and

M, X1 to X4, rings CY1 to CY4, L1 to L4, a1 to a4, R1 to R4, and b1 to b4 are the same as defined in Formula 1.

10. The organometallic compound of claim 8, wherein at least one of rings CY1 to CY4 each comprises a carbene moiety.

11. The organometallic compound of claim 8, wherein rings CY1 to CY4 are each independently a benzene group, a naphthalene group, a pyridine group, a pyridazine group, a pyrimidine group, a pyrazine group, a triazine group, a cyclopentadiene group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, a benzoimidazole group, an imidazopyridine group, an imidazopyrimidine group, imidazotriazine group, an imidazopyrazine group, or an imidazopyridazine group.

12. The organometallic compound of claim 8, wherein

rings CY1 and CY3 are each independently a C4-C20 polycyclic group in which 2 to 4 C3-C8 monocyclic groups are condensed with each other, and

rings CY2 and CY4 are each independently a C3-C8 monocyclic group.

13. The organometallic compound of claim 8, wherein in Formula 1, a moiety represented by is a moiety represented by Formula A1 or Formula A2:

wherein in Formulae A1 and A2,

X12 to X15 are each independently C or N,

* indicates a binding site to M in Formula 1,

*′ indicates a binding site to (L1)a1 in Formula 1, and

*″ indicates a binding site to (L4)a4 in Formula 1.

14. The organometallic compound of claim 8, wherein in Formula 1, a moiety represented by is a moiety represented by Formula A3:

wherein in Formula A3,

* indicates a binding site to M in Formula 1,

*′ indicates a binding site to (L2)a2 in Formula 1, and

*″ indicates a binding site to (L3)a3 in Formula 1.

15. The organometallic compound of claim 8, wherein the organometallic compound comprises at least four deuterium atoms.

16. The organometallic compound of claim 8, wherein at least one L4 is each independently a group represented by one of Formulae 2-1 to 2-3:

wherein in Formulae 2-1 to 2-3,

c4 is an integer from 0 to 4,

R10b is the same as defined in Formula 1,

* indicates a binding site to CY1 in Formula 1, and

*′ indicates a binding site to CY4 in Formula 1.

17. The organometallic compound of claim 8, wherein the organometallic compound is represented by Formula 3-1 or Formula 3-2:

wherein in Formulae 3-1 and 3-2,

X11 and X41 are each independently C or N,

c3 is an integer from 0 to 3,

c4 is an integer from 0 to 4,

c5 is an integer from 0 to 5,

R10c is deuterium, —F, —Cl, —Br, —I, a cyano group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group, a C3-C60 carbocyclic group, or a C1-C60 heterocyclic group,

R10c and R1 are optionally linked to each other to form a C3-C20 carbocyclic group or a C1-C20 heterocyclic group, and

M, X1 to X4, rings CY1 to CY4, L1 to L3, a1 to a3, R1 to R4, b1 to b4, and R10b are the same as defined in Formula 1.

18. The organometallic compound of claim 17, wherein when R10c and R1 are linked to each other, R10c and R1 are linked to each other to form a 9-membered ring.

19. The organometallic compound of claim 8, wherein in Formula 1, a moiety represented by is a moiety represented by one of Formulae 4-1 to 4-3:

wherein in Formulae 4-1 to 4-3,

X11 to X16 and X41 to X45 are each independently C or N,

c3 is an integer from 0 to 3,

c4 is an integer from 0 to 4,

c5 is an integer from 0 to 5,

*′ indicates a binding site to (L1)a1 in Formula 1,

*′ indicates a binding site to (L3)a3 in Formula 1,

R10c is deuterium, —F, —Cl, —Br, —I, a cyano group, a C1-C60 alkyl group, a C2-C60 alkenyl group, a C2-C60 alkynyl group, a C1-C60 alkoxy group, a C3-C60 carbocyclic group, or a C1-C60 heterocyclic group, and

M, X1, X4, R1, R4, and R10b are the same as defined in Formula 1.

20. The organometallic compound of claim 8, wherein the organometallic compound is one of Compounds BD1 to BD33: